Fix empty dropdown

Deselecting the current selected option on a dropdown they were removing the input related to them.
This led to a unexpected cases. The forms were submitted without all required inputs and the label was still indicating an option was selected. This MR fixes that.

See merge request !5927

Before this the dropdowns were not being disabled if the user unselected an option from the allowed to merge/push dropdowns.

No need to update the branch permission if no option is marked on the dropdown

This makes dropdown to look according the dropdowns on the edit form. This options add a tick mark next to the selected option.

Fix inputs not being found due to incorrect class in wrap element

Fixes failing spec

See merge request !5926

Fix Error 500 resulting when loading network graph

`discussion_id` may not be present when the SELECT call for notes does not include this attribute. Don't attempt to set the discussion ID unless the model contains the attribute:

```ruby
irb(main):019:0> notes[0]
  Note Load (10.3ms)  SELECT notes.commit_id, count(notes.id) as note_count FROM "notes" WHERE "notes"."project_id" = $1 AND (noteable_type = 'Commit') GROUP BY notes.commit_id  [["project_id", 13083]]
ActiveModel::MissingAttributeError: missing attribute: discussion_id
```

Closes #21119, #21128

See merge request !5922

`discussion_id` may not be present when the SELECT call for notes
does not include this attribute. Don't attempt to set the discussion ID
unless the model contains the attribute.

Closes #21119, #21128

Fix assorted rspec failures due to stale, cached user permissions

RequestStore is disabled in tests, but the Ability class was caching user permissions based on the user and project ID of previous test runs. Revise code to use RequestStore only if it is active.

See merge request !5919

RequestStore is disabled in tests, but the Ability class was
caching user permissions based on the user and project ID of
previous test runs. Revise code to use RequestStore only if it
is active.

Update gitlab-shell to v3.4.0

Part of Redis Sentinel support: gitlab-org/gitlab-shell#29

See merge request !5920

Backport  changes from gitlab-org/gitlab-ee!581



See merge request !5884

Disable “issue by email” feature until it uses a different token

Separate token being worked on in https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/5914, but too late for 8.11.

See merge request !5915

Call `set_discussion_id` again in DiffNote `before_validation` because the order is important



See merge request !5913

Todos sorting dropdown

Implements #18135 

![todos_sorting](/uploads/bff76827c421628134dfb8b864e47c74/todos_sorting.png)  


- [x] [CHANGELOG](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/CHANGELOG) entry added
- Tests
  - [x] Added for this feature/bug
  - [x] All builds are passing
- [x] Conform by the [style guides](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/CONTRIBUTING.md#style-guides)
- [x] Branch has no merge conflicts with `master` (if you do - rebase it please)
- [x] [Squashed related commits together](https://git-scm.com/book/en/Git-Tools-Rewriting-History#Squashing-Commits)

See merge request !5691

[ci skip]

Koding Integration

## What does this MR do?

Will provide Koding integration with GitLab services. Forked from !4914.

## Are there points in the code the reviewer needs to double check?
I've introduced new layouts which might not be necessary, first time contributor. 

## Why was this MR needed?
We're planning to ship Koding with GitLab.

## What are the relevant issue numbers?
#12759 #14698 

## Screenshots (if relevant)

### Screencasts

http://recordit.co/BDMbhwgxPD
http://recordit.co/By0qiz1ClC

### Enable Koding in Application Settings

![image](/uploads/73a69421105c03aa2b0b47e2617d3fbc/image.png)

### Koding Dashboard
![image](/uploads/6c7dda34792280c0e4791e36af4eba11/image.png)

### Set up Koding Stack
1 - ![image](/uploads/d5c2b93f8e61b5cbffdb06f0267d485f/image.png)
2 - ![image](/uploads/44d9a9b574b8ac0c5eb553fb9653d5da/image.png)

### Run on Koding on Project Page

![image](/uploads/7d2b46221009074ffff75d66d5a1a555/image.png)

### Run in IDE on Merge Requests
![image](/uploads/65eed90c34c34b5fe7ad29ef9c717640/image.png)

## Does this MR meet the acceptance criteria?

- [x] [CHANGELOG](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/CHANGELOG) entry added
- [x] [Documentation created/updated](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/doc/development/doc_styleguide.md)
- [x] Tests
  - [x] Added for this feature/bug
  - [x] All builds are passing
- [x] Conform by the [style guides](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/CONTRIBUTING.md#style-guides)
- [x] Branch has no merge conflicts with `master` (if you do - rebase it please)
- [x] [Squashed related commits together](https://git-scm.com/book/en/Git-Tools-Rewriting-History#Squashing-Commits)

See merge request !5909

17465 Fixed dropdown cursor key navigation

## What does this MR do?
This MR fixes the use of cursor/arrow/enter key events with search dropdowns, allowing a user to navigate up and down the list with the arrow keys and then select their item with the enter key.
It also applies some *minor* scroll user experience fixes, such as resetting the selected dropdown item every time it opens/closes (also stops multiple dropdowns conflicting) and forcing the dropdown scroll to scroll right to the top or bottom depending on whether they have selected the first or last item, respectively.

## Are there points in the code the reviewer needs to double check?
I would like someone with GitLab experience to check over whether this would harm any unique implementations of the GitLabDropdown or SearchAutocomplete.

## Why was this MR needed?
The current version has incorrectly behaving search dropdowns in the navbar, they either do not navigate using the keyboard or do not use the enter keystroke to select a highlighted item.

## What are the relevant issue numbers?
Fixes #17465.
Closes #20752.
Closes #21014.
**Contributes** to #20754.

## Screenshots (if relevant)
![17465.mp4](/uploads/1145abec226036abbaaa4aa46020f52b/17465.mp4)

See merge request !4781

Koding: #index: landing page for Koding integration

If enabled it will provide a link to open remote Koding instance url
for now we are also providing the sneak preview video for how
integration works in detail.

Repository: check whether .koding.yml file exists on repository

Projects: landing page: show Run in IDE (Koding) button if repo has stack file

Projects: MR: show Run in IDE Koding button if repo has stack file on active branch

ProjectHelpers: add_koding_stack: stack generator for provided project

With this helper we will auto-generate the required stack template
for a given project. For the feature we can request this base template
from the running Koding instance on integration.

Currently this will provide users to create a t2.nano instance on aws
and it'll automatically configures the instance for basic requirements.

Projects: empty state and landing page provide shortcuts to create stack

projects_helper: use branch on checkout and provide an entry point

This ${var.koding_queryString_branch} will be replaced with the branch
provided in query string which will allow us to use same stack template
for different branches of the same repository.

ref: https://github.com/koding/koding/pull/8597/commits/b8c0e43c4c24bf132670aa8a3cfb0d634acfd09b

projects_helper: provide sha info in query string to use existing vms

With this change we'll be able to query existing vms on Koding side
based on the commit id that they've created.

ref: https://github.com/koding/koding/pull/8597/commits/1d630fadf31963fa6ccd3bed92e526761a30a343

Integration: Docs: Koding documentation added

Disable /koding route if integration is disabled

Use application settings to enable Koding

Projects_helper: better indentation with strip_heredoc usage

Projects_helper: return koding_url as is if there is no project provided

current_settings: set koding_enabled: false by default

Koding_Controller: to render not_found once integration is disabled

Dashboard_specs: update spec for Koding enabled case

Projects_Helper: make repo dynamic

ref: https://github.com/koding/koding/pull/8597/commits/4d615242f45aaea4c4986be84ecc612b0bb1514c

Updated documentation to have right format

1. EE access control specs are significantly different, so this is a way
   to reduce potential merge conflicts. EE and CE specs go in separate files.

Make all future skipped builds as processable when retrying a build

## What does this MR do?

Makes a builds that are marked as skipped when a pipeline is processed to be reprocessed by changing their's state to created.

## Why was this MR needed?

Currently retry is broken. When you retry a build of pipeline it will succeed and be marked as succeeded, when the next stages should be triggered.

Fixes https://gitlab.com/gitlab-org/gitlab-ce/issues/21066

See merge request !5879

Merge branch '21010-emailsonpushworker-incorrectly-claims-deleted-a-commit-after-a-push' into 'master'

Resolve "EmailsOnPushWorker incorrectly claims deleted a commit after a push"

## What does this MR do?

Fix the comparison order in the emails on push worker, so regular pushes don't show a message about force pushing.

## Are there points in the code the reviewer needs to double check?

Don't think so, it was just a typo: `after_sha` should map to the `source_branch` argument, because it's the head of the comparison.

## Why was this MR needed?

To fix a regression!

## What are the relevant issue numbers?

Closes #21010.

## Does this MR meet the acceptance criteria?

- [x] ~~[CHANGELOG](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/CHANGELOG) entry added~~
- [x] ~~[Documentation created/updated](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/doc/development/doc_styleguide.md)~~
- [x] ~~API support added~~
- Tests
  - [x] Added for this feature/bug
  - [ ] All builds are passing
- [x] Conform by the [style guides](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/CONTRIBUTING.md#style-guides)
- [x] Branch has no merge conflicts with `master` (if you do - rebase it please)
- [x] [Squashed related commits together](https://git-scm.com/book/en/Git-Tools-Rewriting-History#Squashing-Commits)

See merge request !5894