Move Ruby endpoints to OPT_OUT

See merge request gitlab-org/gitlab-ce!17561

Backport of "Geo: Ignore remote stored objects when calculating counts"

See merge request gitlab-org/gitlab-ce!17581

add nginx_status monitoring details

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

Part of: gitlab-org/gitaly#476

Part of: gitlab-org/gitaly#476

Part of: gitlab-org/gitlab-ce!17561

Part of: gitlab-org/gitaly#540

Part of: gitlab-org/gitaly#546

Part of: gitlab-org/gitaly#779

Part of: gitlab-org/gitaly#541

Part of gitlab-org/gitaly#324

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

Part of gitlab-org/gitaly#616

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