This is basically a copy of the API for project clusters.

The current approach requires catching exceptions to handle these errors
and callers are already handling model validations so it seems more
appropriate.  Also it seemed to convoluted to add this logic directly to
the model since the model needs to check too many possible associations
to determine whether or not there are more than one cluster since the
model doesn't know what it's being created on. Additionally we only
wanted to validate during create to avoid the risk of existing models
becoming invalid by many different edge cases.

After review, heading was changed and links to
it needed to be updated, and minor tweaks to
the issues docs such as note formatting

Cache Flipper feature flags in L1 and L2 caches

See merge request gitlab-org/gitlab-ce!30276

Updates the yaml docs to match the environment docs regarding `GIT_STRATEGY=none`

See merge request gitlab-org/gitlab-ce!30283

Docs: Update Auto Deploy link to page instead of redirect

See merge request gitlab-org/gitlab-ce!30325

In https://gitlab.com/gitlab-com/gl-infra/production/issues/928, we saw
a significant amount of network traffic and CPU usage due to Redis
checking feature flags via Flipper. Since these flags are hit with every
request, the overhead becomes significant. To alleviate Redis overhead,
we now cache the data in the following way:

* L1: A thread-local memory store for 1 minute
* L2: Redis for 1 hour

Notes that `GIT_STRATEGY` should be set to `none` so that the
job doesn't fail when triggered automatically when the branch
is deleted.

Backport EE MR that improves end-to-end tests

See merge request gitlab-org/gitlab-ce!30320

Limit amount of JUnit tests returned

Closes #64035

See merge request gitlab-org/gitlab-ce!30274

Currently, we do not cap amount of tests returned to frontend,
thus in some extreme cases we can see a MBs of data stored in Redis.

This adds an upper limit of 100 tests per-suite.

We will continue showing the total counters correctly,
but we will limit amount of tests that will be presented.

Rename Release groups in issue_workflow.md

See merge request gitlab-org/gitlab-ce!30293

Change occurrence of Sidekiq::Testing.inline!

Closes #22991

See merge request gitlab-org/gitlab-ce!29890

- Change it to perform_enqueued_jobs

https://gitlab.com/gitlab-org/gitlab-ee/merge_requests/14533

Fix order-dependent spec failure in appearance_spec.rb

Closes #64083

See merge request gitlab-org/gitlab-ce!30323

When file_mover_spec.rb ran, it would initialize fog-aws with
`Fog::AWS::Storage::Real` service instead of `Fog::AWS::Storage::Mock`
because `Fog.mock!` was not called. Ensure that we use
`stub_uploads_object_storage` to prevent that from happening.

Closes https://gitlab.com/gitlab-org/gitlab-ce/issues/64083

Add GetCommitSignatures feature flag

See merge request gitlab-org/gitlab-ce!29288

Put a failed example from appearance_spec in quarantine

See merge request gitlab-org/gitlab-ce!30318

Cache PerformanceBar.allowed_user_ids list locally instead of in Redis

See merge request gitlab-org/gitlab-ce!30304

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

Add Grafana to Admin > Monitoring menu when enabled

Closes #61005

See merge request gitlab-org/gitlab-ce!28937

Add salesforce logo for salesforce SSO

Closes #62607

See merge request gitlab-org/gitlab-ce!28857

Re-align CE and EE API docs

See merge request gitlab-org/gitlab-ce!30294

Only save Peek session in Redis when Peek is enabled

See merge request gitlab-org/gitlab-ce!30306

Move error_tracking_frontend specs to Jest

Closes #61797

See merge request gitlab-org/gitlab-ce!30211

Update TEST_HOST import paths. Tests all pass

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

Enable terminals button for group clusters

Closes #55487

See merge request gitlab-org/gitlab-ce!30255

Migrate markdown header_spec.js to Jest

See merge request gitlab-org/gitlab-ce!30228

Enable AsciiDoc syntax highlighting (using Rouge)

Closes #32635

See merge request gitlab-org/gitlab-ce!29835

Update TODO: allow_collaboration column renaming

See merge request gitlab-org/gitlab-ce!30291

rename `discussion` to `thread`

Closes #55953

See merge request gitlab-org/gitlab-ce!29553

Fix golint command in Go guide doc to be recursive

See merge request gitlab-org/gitlab-ce!30262