For both groups_controller and admin/groups_controller

This setting is at the group level only. The default is specified to
be maintainers and owners.

**Specs only**, all failing.

All specs passing

- Change the two existing feature examples that create a subgroup to
  elucidate that the owner is creating the subgroup

- Nest two more specs inside the 'subgroup support' context detailing
  what happens when a maintainer attempts to add a subgroup (one with
  subgroup support, and one without)

Fix Gitaly auto-detection caching

Closes #64802

See merge request gitlab-org/gitlab-ce!30954

Remove duplicate buttons

Closes #64160

See merge request gitlab-org/gitlab-ce!30757

Document database review process

See merge request gitlab-org/gitlab-ce!30405

See https://gitlab.com/gitlab-com/gl-infra/infrastructure/issues/6069

Get rid of `worker_label` in RubySampler

See merge request gitlab-org/gitlab-ce!30942

Avoid increasing redis counters when usage_ping is disabled

See merge request gitlab-org/gitlab-ce!30949

If `GitalyClient#can_use_disk?` returned `false`, it was never cached
properly and led to excessive number of Gitaly calls. Instead of using
`cached_value.present?`, we need to check `cached_value.nil?`.

Closes https://gitlab.com/gitlab-org/gitlab-ce/issues/64802

Fixes the alignment on reports

See merge request gitlab-org/gitlab-ce!30839

- Removes a justify-center class that causes reports to centrally align

Centers loading icon in CI action

Closes #64265

See merge request gitlab-org/gitlab-ce!30947

Use `issuable_path` helper

See merge request gitlab-org/gitlab-ce!30913

Resolve "Export frontend fixtures as pipeline artifact"

Closes #64722 and #59166

See merge request gitlab-org/gitlab-ce!30917

We have Prometheus::PidProvider which sets correct worker id for a
process, so such implementation of `worker_label` in the sampler is
obsolete.

Fix regression in re-naming files

Closes #64784

See merge request gitlab-org/gitlab-ce!30941

Adjust redis cache metrics

See merge request gitlab-org/gitlab-ce!30572

* Remove `controller` and `action` labels from duration histogram.
* Create a new simple counter for `controller` and `action`.
* Adjust histogram buckets to observe smaller response times.

Better scope end-to-end test

See merge request gitlab-org/gitlab-ce!30897

Better scope another end-to-end test

See merge request gitlab-org/gitlab-ce!30896

Quarantine failing "rebase_merge_request_spec.rb"

See merge request gitlab-org/gitlab-ce!30933

Web IDE Usage Ping for Create SMAU

Closes #63886

See merge request gitlab-org/gitlab-ce!30800

The actions tracked in the web IDE are:
- creation of commits
- creation of merge requests
- projects loaded

Better scope end-to-end test

See merge request gitlab-org/gitlab-ce!30895

Add a note about private_profile changes in 12.1

Closes #64613

See merge request gitlab-org/gitlab-ce!30772