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

  - Includes documentation and tests

Use NotificationSetting::EMAIL_EVENTS for params

Closes #21043

Also, mutualize AccessRequests and Members endpoints for Group &
Project.
New API documentation for the AccessRequests endpoints.
Signed-off-by: NRémy Coutable <remy@rymai.me>

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

Also a couple of minor edits for this branch are included

Basically:

    GET /api/projects/:id/artifacts/:ref_name/:build_name

Also added tests for it.

Docs also added.

This only supports Issues and MergeRequests right now because of the
consistency of the routes those models provide.

This reverts commit 06e0ef07

This reverts commit 3e991230.

# Conflicts:
#	app/models/project.rb

Closes #15638

- Fix naming of API::CommitStatuses
- Ensure we use require_dependency instead of require
- Ensure the namespace is right in lib/api/api.rb, otherwise, we
  might require Grape::API::Helpers which defines the `#params` method.
  This is to avoid requiring a file multiple times and getting an "Already
  initialized constant" error.
Signed-off-by: NRémy Coutable <remy@rymai.me>

This reverts commit 0a280158.

- So that the server doesn't have to be restarted for every change in dev.

- Makes the MR easier to read; this can go in a separate MR
- This is a (sort of) revert of 99bea01

- add feature to list runners
- add feature to show runners details
- add feature to delete runner
- add feature to update runner