Add back Gitaly feature flag for cache invalidation

See merge request gitlab-org/gitlab!22106

Part of https://gitlab.com/gitlab-org/gitaly/issues/2292

Related to https://gitlab.com/gitlab-org/gitaly/issues/2288

This change is essentially a revert of
https://gitlab.com/gitlab-org/gitlab/merge_requests/18766. Due to an
issue found in production (see
https://gitlab.com/gitlab-com/gl-infra/production/issues/1501#note_262058610),
the cache invalidator needs to be disabled until the cache walker is
able to remove empty directories. This feature flag will allow us to
reenable the cache invalidator when we are ready to test the updated
cache walker.

Improve specs by defining anonymous instead of named classes

Closes #119104

See merge request gitlab-org/gitlab!22094

Update comments, specify new path to spec

See merge request gitlab-org/gitlab!22223

Decorate rich_text with word-diff highlights

See merge request gitlab-org/gitlab!22182

Document `CI_MERGE_REQUEST_EVENT_TYPE`

Closes #37482

See merge request gitlab-org/gitlab!22145

Add changes to default behaviour in docs

See merge request gitlab-org/gitlab!21975

docs - Added myself (Jan Urbanec) as czech proofreader.

See merge request gitlab-org/gitlab!21906

Show sample metrics for an environment without prometheus

Closes #36255

See merge request gitlab-org/gitlab!22133

Fix GitLab Pages deployments not working

Closes #12166 and #121660

See merge request gitlab-org/gitlab!22228

Add expectation in Gitlab::ImportExport::GroupTreeSaver specs

See merge request gitlab-org/gitlab!22214

Fix setup order in Elasticsearch docs

See merge request gitlab-org/gitlab!21930

The deployment of
https://gitlab.com/gitlab-org/gitlab/merge_requests/20154 broke new
deployments of GitLab Pages. The call to
`project.feature_available?(:pages_size_limit)` failed with this error:

```
Use `License.feature_available?` for features that cannot be
restricted to only a subset of projects or namespaces
```

Since `GLOBAL_FEATURES` includes `pages_size_limit`, we must call
`License.feature_available?(:pages_size_limit)` instead to be consistent
with `EE::GlobalPolicy`.

Closes https://gitlab.com/gitlab-org/gitlab/issues/12166

Refactor Prometheus Adapter to take in cluster

See merge request gitlab-org/gitlab!22191

Add Gitlab version and revision to export

See merge request gitlab-org/gitlab!22108

Revert "Merge branch 'eb-no-keep-report-artifacts' into 'master'"

Closes #121663

See merge request gitlab-org/gitlab!22225

Add Istio API group to kubeclient

See merge request gitlab-org/gitlab!22185

Relates to https://gitlab.com/gitlab-org/gitlab/issues/33559

Implement saving config content for pipelines

See merge request gitlab-org/gitlab!21827

Besides .gitlab-ci.yml file,
there are other factors that affect pipeline creation.
So we need to store the content of its configuration.

Merge branch '34638-remove-ignoring-of-merge_requests_require_code_owner_approval-column-on-projects' into 'master'

Resolve "Remove ignoring of `merge_requests_require_code_owner_approval` column on projects"

See merge request gitlab-org/gitlab!22197

This reverts merge request !21553

Start to use the 'rules' keyword for the 'package-and-qa' job

See merge request gitlab-org/gitlab!21945

Replace Vue key=index in licenses list table

See merge request gitlab-org/gitlab!21566

**Why?**

In Vue, lists are not re-rendered, but patched when new props come. This
can cause issues when items which are actually different share the same key.

- https://gitlab.com/gitlab-org/gitlab/issues/39126

Raise support bot permission to reporter

See merge request gitlab-org/gitlab!21948

Certify the 5K user reference architecture in the docs

Closes gitlab-org/quality/performance#126

See merge request gitlab-org/gitlab!21526

Certify the 2K user reference architecture in the docs

Closes gitlab-org/quality/performance#58

See merge request gitlab-org/gitlab!21525

Remove after_initialize, before_validation for discussion_id on Note

See merge request gitlab-org/gitlab!22128

- We're already overridding the `discussion_id` method in Note.  The
  after_initialize callback is meant to ensure there's a discussion_id
  for all notes if there wasn't one created (or it got deleted?)

- after_initialize runs Ruby code for _every_ instantiation whether it
  needs to or not.  I've found this to cause performance problems.

When service desk is enabled suport bot receives
reporter permissions.
This allows quick actions present on service desk issue
templates to be applied.

Return 503 error when metrics dashboard has no connectivity

Closes #39162

See merge request gitlab-org/gitlab!22140

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

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

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