Merge branch '324160-geo-zero-downtime-upgrades-step-gitlab-rake-db-migrate-fails-in-13-9-3' into 'master'

Fix zero-downtime upgrade from 13.8.x to 13.9.3

See merge request gitlab-org/gitlab!56352

Added details about words the version bullet must include

See merge request gitlab-org/gitlab!56388

Update gitlab-experiment to version 0.5.0 [RUN ALL RSPEC] [RUN AS-IF-FOSS]

See merge request gitlab-org/gitlab!55916

Add example requests for publishing packages with deploy tokens

See merge request gitlab-org/gitlab!56396

Remove obsolete DOMContentLoadedEventListener

See merge request gitlab-org/gitlab!56371

Wiki: #find_file defaults to HEAD over master

See merge request gitlab-org/gitlab!56354

Restore publishing behavior for Gon

See merge request gitlab-org/gitlab!56374

Complete rewrite of snippets page

See merge request gitlab-org/gitlab!56262

The page needed major reworking to have some sort of logical flow,
and follow CTRT. It also needed several old screenshots removed.

Add helper for batched background migrations

See merge request gitlab-org/gitlab!55872

Add a new migration helper to simplify starting a batched background
migration, by defaulting values that don't always need to be specified.

Gem download route

See merge request gitlab-org/gitlab!55143

Remove Starter reference

See merge request gitlab-org/gitlab!56168

Lower multipart log threshold from 500 MB to 100 MB

See merge request gitlab-org/gitlab!56390

This also makes the threshold configurable via an environment variable
`RACK_MULTIPART_LOGGING_BYTES`.

This will help identify uploads in
https://gitlab.com/gitlab-com/gl-infra/infrastructure/-/issues/12802.

Update feature flag documentation for compliance framework

See merge request gitlab-org/gitlab!56253

Moving process docs for feature flags to handbook

See merge request gitlab-org/gitlab!55891

- the feature flag working group is consolidating and clarifying the
  existing feature flag documentation. See
https://gitlab.com/gitlab-org/gitlab/-/issues/249129#note_523228764 for
more details. This commit removes the process documentation and
https://gitlab.com/gitlab-com/www-gitlab-com/-/merge_requests/76630
moves it to the handbook.

Remove user profile doc link

See merge request gitlab-org/gitlab!56393

Use a default branch that's not "master" in template

See merge request gitlab-org/gitlab!55949

Gem download route for rubygems package registry

Remove Starter reference from Project page

See merge request gitlab-org/gitlab!56251

Remove Starter references from Project page.

Update the maven package finder

See merge request gitlab-org/gitlab!56346

Remove .block class from right sidebar blocks

See merge request gitlab-org/gitlab!55886

Rubygems dependencies endpoint

See merge request gitlab-org/gitlab!55917

Adds rubygems dependency resolver service
and route to return dependencies for
requested gems.

Allow anonymous access to public Conan packages

See merge request gitlab-org/gitlab!54047

- Allow access to ping endpoint without a token
- Allow access to download endpoints without a token, if the project
  is public
- Instead of throwing UnauthorizedError when no token is provided,
  continue with anonymous privileges
- Update tests to reflect the above changes
- Add test for downloading without a token

Start removing extends from SCSS

See merge request gitlab-org/gitlab!55447

Rename with_scanners to with_scanner_external_ids

See merge request gitlab-org/gitlab!56283

Add headers to test report widget

See merge request gitlab-org/gitlab!56252

Allow users to specify environment tier via .gitlab-ci.yml

See merge request gitlab-org/gitlab!55723

Geo: Fix syncing direct download remote stored Blobs

See merge request gitlab-org/gitlab!55775

Use gitlab-fog-google instead of upstream fog-google gem

See merge request gitlab-org/gitlab!56245