Using the relation `Project#source_of_merge_requests` in
`Ci::CreatePipelineService`

That way we take advantage of all the `ActiveRecord::Relation` magic

The query becomes a lot simpler if we can check the branch name as
well instead of having to load all branch names.

When an MR is created using `allow_maintainer_to_push`, we enable some
abilities while the MR is open.

This should allow every user with developer abilities on the target
project, to push to the source project.

When a project is not private, and the source branch not protected the
user can now select the option to allow maintainers to push to this
branch

This flag will allow maintainers of a project to push to specific
branches of a fork of a project

add nginx_status monitoring details

See merge request gitlab-org/gitlab-ce!17596

Use persisted/memoized value for MRs sha's instead of doing git lookups

See merge request gitlab-org/gitlab-ce!17555

Add discussion API

See merge request gitlab-org/gitlab-ce!17510

Resolve "Update language about version check in admin settings and docs"

Closes #43486

See merge request gitlab-org/gitlab-ce!17535

Add CommonMark markdown engine

See merge request gitlab-org/gitlab-ce!14835

Keep track of projects a user interacted with

Closes #43460

See merge request gitlab-org/gitlab-ce!17327

Show plugins list on system hooks page

Closes #40812

See merge request gitlab-org/gitlab-ce!17518

* adds basic discussions API for issues and snippets
* reorganizes notes specs (so same tests can be used for all noteable types - issues, MRs, snippets)

Unify deployment_platform interface with EE

See merge request gitlab-org/gitlab-ce!17594

Fix group boards migration name

See merge request gitlab-org/gitlab-ce!17592

Count discussions on issues and merge requests as contributions for the contributions calendar

See merge request gitlab-org/gitlab-ce!17557

Resolve "Update clipboard button component not to render default css classes"

Closes #43502

See merge request gitlab-org/gitlab-ce!17529

Bump Gitlab Shell to v6.0.4

Closes #43739

See merge request gitlab-org/gitlab-ce!17582

This had the same name in EE, so give it a different name in CE.

CI charts now include the current day

Closes #42921

See merge request gitlab-org/gitlab-ce!17032

Make --prune a configurable parameter in fetching a git remote

See merge request gitlab-org/gitlab-ce!17346

The MergeRequestWidgetEntity is used a lot in AJAX requests, and shaving
that git operation will hopefully translate in a performance improvement

Remove common_vue bundle

See merge request gitlab-org/gitlab-ce!17551

Gitlab::Utils - backport `.ensure_array_from_string` from EE

See merge request gitlab-org/gitlab-ce!17574

Changes after review

Gitaly N+1 notice on Banzai filtering

See merge request gitlab-org/gitlab-ce!17540

Merge branch 'move-pipeline_default-update_head_pipeline_for_merge_request-queue-to-pipeline_processing-namespace' into 'master'

Move update_head_pipeline_for_merge_request queue to `pipeline_processing` namespace

Closes #43919

See merge request gitlab-org/gitlab-ce!17572