And add changelog entry.

Use strings for the ApplicationSetting properties:
 - restricted_visibility_levels
 - default_project_visibility
 - default_snippet_visibility
 - default_group_visibility

Because environments also expose the project, ensure the projects are
exposed as they were before in API v3.

Instead of exposing the VisibilityLevel as Integer, expose it as
String `visibility`.

Instead of exposing the VisibilityLevel as Integer, expose it as
String `visibility` for Project and ProjectSnippet.

Filter queries also accept the `visibility` as String instead of
`visibility_level` as Integer.

Also remove the `public` boolean.

For the API, the VisibilityLevel will be exposed as String instead of
Integer. So add the string values and method to translate a level
integer to a string.

CE Upstream - Wednesday

See merge request !1330

Use v4 endpoint in API docs

See merge request !1338

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

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

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

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

Rename MWBS to MWPS (EE port)

See merge request !1332

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

Remove the newrelic gem

See merge request !1335

The frontend should use the v3 API for now

Closes gitlab-ce#28863

See merge request !1331

Deploy boards backend

Closes #1589

See merge request !1278

Custom empty exception class cop

See merge request !1328

 Rename column in the database
 Rename fields related to import/export feature
 Rename API endpoints
 Rename documentation links
 Rename the rest of occurrences in the code
 Replace the images that contain the words "build succeeds" and docs referencing to them
 Make sure pipeline is green and nothing is missing.

# Conflicts:
#	app/controllers/projects/merge_requests_controller.rb
#	app/serializers/merge_request_entity.rb
#	app/services/merge_requests/merge_when_pipeline_succeeds_service.rb
#	app/services/merge_requests/refresh_service.rb
#	app/views/projects/merge_requests/merge.js.haml
#	app/views/projects/merge_requests/widget/open/_accept.html.haml
#	doc/api/merge_requests.md
#	doc/api/projects.md
#	lib/api/entities.rb
#	lib/api/v3/entities.rb
#	lib/api/v3/merge_requests.rb
#	spec/services/merge_requests/merge_when_pipeline_succeeds_service_spec.rb
#	spec/services/merge_requests/refresh_service_spec.rb

Add note about how to use or escape variables inside other variables

See merge request !1324

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

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

[ci skip]

[ci skip]

Restructure Pages docs index and getting started guides

See merge request !1329

Use rollout_status_path provided in environment to fetch the data instead of hardcoded endpoint

See merge request !1323

[ci skip]

Restructure pages docs

Closes #28688

See merge request !9527

#25437 Allow posting of just an emoji in comment; add /award slash command

Closes #25437

See merge request !9382

[ci skip]

From the Ruby style guide:

    # bad
    class FooError < StandardError
    end

    # okish
    class FooError < StandardError; end

    # good
    FooError = Class.new(StandardError)

This cop does that, but only for error classes (classes where the
superclass ends in 'Error'). We have empty controllers and models, which
are perfectly valid empty classes.