Fixes #23895.

Signed-off-by: NDmitriy Zaporozhets <dmitriy.zaporozhets@gmail.com>

It consolidates these endpoints:
 - /projects
 - /projects/owned
 - /projects/visible
 - /projects/starred
 - /projects/all

Into the /projects endpoint using query parameters.

Signed-off-by: NDmitriy Zaporozhets <dmitriy.zaporozhets@gmail.com>

Follow-up to d05dd81b which changed the nested namespaces in projects
to use API::Entities::Namespace instead of exposing all fields.

Fixes #27730

Signed-off-by: NDmitriy Zaporozhets <dmitriy.zaporozhets@gmail.com>

The create and edit actions for projects had these parameters:

- `public` (optional) - if true same as setting `visibility_level = 20`
- `visibility_level` (optional)

Remove the `public` parameter to avoid contradiction.

Store the value in application settings.
Expose the value to Workhorse.

Applied in example response for create, update, and delete operations

Fixes #27643

Signed-off-by: NDmitriy Zaporozhets <dmitriy.zaporozhets@gmail.com>

New endpoints are:

POST :project_id/(issues|merge_requests)/(:issue_id|:merge_request_id)/time_estimate"

POST :project_id/(issues|merge_requests)/(:issue_id|:merge_request_id)/reset_time_estimate"

POST :project_id/(issues|merge_requests)/(:issue_id|:merge_request_id)/add_spent_time"

POST :project_id/(issues|merge_requests)/(:issue_id|:merge_request_id)/reset_spent_time"

GET  :project_id/(issues|merge_requests)/(:issue_id|:merge_request_id)/time_stats"

- Use IssuesFinder for the /issues API resouce
- Tests for iid filter in project issues API resource
- Tests for No Milestone filter in issues API resources
  The "No Milestone" case was not previously tested, and the `/issues`
  resource did not support the the `milestone` parameter.
- Return issues where all labels match from the issues and project issues
  API resources, like the group issues resource already does. See
  https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/6825#note_17474533Signed-off-by: NRémy Coutable <remy@rymai.me>

This MR enables rendering of PlantUML diagrams in Asciidoc documents. To add a
PlantUML diagram all we need is to include a plantuml block like:

```
[plantuml, id="myDiagram", width="100px", height="100px"]
--
bob -> alice : ping
alice -> bob : pong
--
```

The plantuml block is substituted by an HTML img element with *src* pointing to
an external PlantUML server.

This MR also add a PlantUML integration section to the Administrator -> Settings
page to configure the PlantUML rendering service and to enable/disable it.

Closes: #17603

curl --request DELETE --header "PRIVATE-TOKEN: 9koXpg98eAheJpvBs5tK" "https://gitlab.example.com/api/v3/projects/1/environments/1"  wil 404

* Use standard helpers for finding group and project

This adds counters for build artifacts and LFS objects, and moves
the preexisting repository_size and commit_count from the projects
table into a new project_statistics table.

The counters are displayed in the administration area for projects
and groups, and also available through the API for admins (on */all)
and normal users (on */owned)

The statistics are updated through ProjectCacheWorker, which can now
do more granular updates with the new :statistics argument.

Signed-off-by: NRémy Coutable <remy@rymai.me>