Push rules can be treated as a type of settings, such as
application_settings, project_settings, etc. There must be only one for
a given project. Therefore, it would be better to just expose the update
interface and let the creation handled behind the scene.

This commit extracts project push rule create and update logic to
a dedicated service class. This change allows to centralize auditing
and logging of actions from Project Push Rule controller and API.

The POST and PUT API can handle both create and update without raising
`unprocessable_entity` and `not_found` error respectively. Since the
user can only manage push rule via project id and they can only ever
create one, this change reduces coordinating POST request before PUT
request.

Enable optimized merged at count FF by default

See merge request gitlab-org/gitlab!53704

Remove unnecessary Rubocop disable

See merge request gitlab-org/gitlab!54001

Add video of CI minutes overview

See merge request gitlab-org/gitlab!53839

Expose default value stream configuration

See merge request gitlab-org/gitlab!53688

Provides the default values stream stage configs
from the backend via data attributes

Resolve "Remove re-use of IterationsResolver"

See merge request gitlab-org/gitlab!53171

Fix jest time reporting by resetting environment

See merge request gitlab-org/gitlab!54033

Update pipeline route in spec

See merge request gitlab-org/gitlab!53865

Cleanup policies: put the unfinished cleanup state in case of an error

See merge request gitlab-org/gitlab!53853

Update docs with new UI for GitLab Jira connect app

See merge request gitlab-org/gitlab!53206

Update docs with same copy change we have inside the app

Update Webpack core packages

See merge request gitlab-org/gitlab!53892

Add Clair deprecation note

See merge request gitlab-org/gitlab!54032

Add deprecation notice to service templates

See merge request gitlab-org/gitlab!53334

Remove Starter references from version sections

See merge request gitlab-org/gitlab!53989

Fix top space on tree table

See merge request gitlab-org/gitlab!54025

Update commits.md to add introduction

See merge request gitlab-org/gitlab!51017

Add helper for clearing blank model attributes before validation

See merge request gitlab-org/gitlab!53681

Update User Cap docs to remove the feature flag

See merge request gitlab-org/gitlab!53793

Apply GitLab UI button styles to buttons in group settings

See merge request gitlab-org/gitlab!51781

Update Gitaly version

See merge request gitlab-org/gitlab!54016

MR: https://gitlab.com/gitlab-org/gitlab/-/merge_requests/54025

Deprecate domain_config_source for GitLab Pages

See merge request gitlab-org/gitlab!53689

Remove obsolete DOMContentLoadedEventListener

See merge request gitlab-org/gitlab!53869

Reduce the complexity of computed props in pipelines_table_row

See merge request gitlab-org/gitlab!53904

Update group name in metadata

See merge request gitlab-org/gitlab!53998

Change Provision to License in metadata.

Apply new GitLab UI for buttons in pipeline page

See merge request gitlab-org/gitlab!53364

Move CI pipeline enum under CE

See merge request gitlab-org/gitlab!53938

Add semgrep sast analyzer docs and template

See merge request gitlab-org/gitlab!53815

Fix unknown constant in compliance dashboard seed

See merge request gitlab-org/gitlab!54012

Remove dead code in issues_controller#create RUN AS-IF-FOSS

See merge request gitlab-org/gitlab!53949