In certain cases, GitLab can miss a PostReceive invocation the first
time a branch is pushed. When this happens, the "branch created" hooks
are not run, which means various features don't work until the branch
is deleted and pushed again.

This MR changes the `Git::BranchPushService` so it checks the cache of
existing branches in addition to the `oldrev` reported for the branch.
If the branch name isn't in the cache, chances are we haven't run the
service yet (it's what refreshes the cache), so we can go ahead and
run it, even through `oldrev` is set.

If the cache has been cleared by some other means in the meantime, then
we'll still fail to run the hooks when we should. Fixing that in the
general case is a larger problem, and we'd need to devote significant
engineering effort to it.

There's a chance that we'll run the relevant hooks *multiple times*
with this change, if there's a race between the branch being created,
and the `PostReceive` worker being run multiple times, but this can
already happen, since Sidekiq is "at-least-once" execution of jobs. So,
this should be safe.

Add script for creating an MR with many commits

See merge request gitlab-org/gitlab-ce!29762

Docs: Fixes all the alert boxes in "reduce repo size"

Closes #61472

See merge request gitlab-org/gitlab-ce!29680

Fix flaky time related failure in spec/models/ci/pipeline_schedule_spec.rb

Closes #62760

See merge request gitlab-org/gitlab-ce!29778

Remove support for creating non-RBAC kubernetes clusters

Closes #55902

See merge request gitlab-org/gitlab-ce!29614

Also does a lot of cleanup and refactoring

Fix IDE commit to use start_ref

See merge request gitlab-org/gitlab-ce!29769

Resolve "The GraphQL query for the MR popover failes on the frontend"

Closes #63261

See merge request gitlab-org/gitlab-ce!29712

Also removes test from quarantine

Enforce template inclusion in pipelines - CE

See merge request gitlab-org/gitlab-ce!29296

Search issuables by iids

Closes #39908 and #30974

See merge request gitlab-org/gitlab-ce!28302

Only push to assets-compile-cache when in master

See merge request gitlab-org/gitlab-ce!28854

Backport EE changes to config/application.rb

See merge request gitlab-org/gitlab-ce!29557

Add index to events and audit_events tables

Closes gitlab-com/Product#309

See merge request gitlab-org/gitlab-ce!29194

Update GraphQL document to mention that epics are supported

See merge request gitlab-org/gitlab-ce!29777

Add note about nested variables for GIT_CLONE_PATH

See merge request gitlab-org/gitlab-ce!29590

The variable $GIT_CLONE_PATH does not support nested variables, it will
only expand the variables once, not more.

reference https://gitlab.com/gitlab-org/gitlab-runner/issues/4319

[QA] Test push limit with admin user

Closes gitlab-org/quality/staging#37

See merge request gitlab-org/gitlab-ce!29036

Uses `:requires_admin` metadata to specify that a test needs
an admin user.

Sets the push file size limit test to require an admin user.

With an admin access token set as the env var
GITLAB_QA_ADMIN_ACCESS_TOKEN, the push size
limit test now only uses the API and CLI

Fixing an old quarantined test

Closes gitlab-org/quality/staging#50

See merge request gitlab-org/gitlab-ce!28643

Allow switching clusters between managed/unmanaged

Closes #60617

See merge request gitlab-org/gitlab-ce!29322

Make Kubernetes service templates readonly

See merge request gitlab-org/gitlab-ce!29044

We are deprecating this service in favor of instance wide clusters.
Therefore we removed some code that is not anymore needed for a
readonly cluster and also we added some flags to allow for this
deprecation. These flags are to be removed in the next release when
we finally completelly remove KubernetesService.

Migrate Kubernetes service integration templates to clusters

See merge request gitlab-org/gitlab-ce!28534

Index on created_at, author_id

Updated docs for Merge Trains

See merge request gitlab-org/gitlab-ce!29771

Any resources created while the cluster was managed
will be untouched, allowing users to set/unset this
flag as they please.

Don't use Kubernetes namespaces with no token

See merge request gitlab-org/gitlab-ce!29643

Add index on invite-email to members

See merge request gitlab-org/gitlab-ce!29768

CE port of "Add test for git http operations for SSO enforced SAML group"

See merge request gitlab-org/gitlab-ce!29550

[CE] Validate page after visit in block

See merge request gitlab-org/gitlab-ce!29524

Expose currently supported events properly on services API

Closes #56737

See merge request gitlab-org/gitlab-ce!29736

Refresh service_account_token for kubernetes_namespaces

See merge request gitlab-org/gitlab-ce!29657

note that todos are not affected by GitLab Notification Email settings

See merge request gitlab-org/gitlab-ce!29539