Add audit log for feature flags

See merge request gitlab-org/gitlab-ee!9487

* Move feature flag CRUD into service objects
* Create audit logs FF CRUD
* Calculate environment scope difference and add audit logs for changed
* scopes on update
* Add specs
* Use custom_message in feature flag audit events
* feature flags html actions and @feature_flag variable

Add filtering merge requests by approvers

See merge request gitlab-org/gitlab-ee!9468

This reverts commit 6d5c21e83257e47c03a70f27bbfbca59570608d4.

Docs: Introduction to continuous methods and GitLab CI/CD

Closes #58394

See merge request gitlab-org/gitlab-ce!25611

- Pipeline status
- Job running
- Rollback button

Revert "Merge branch 'sh-show-pre-receive-error-merge' into 'master'"

See merge request gitlab-org/gitlab-ce!25895

Expect masked TOKENs in EE specs

Closes #10274

See merge request gitlab-org/gitlab-ee!9924

This reverts merge request !25708

Upgrade Gitaly to v1.26.0

See merge request gitlab-org/gitlab-ce!25890

Merge branch '58304-extend-the-snowplow-event-tracking-documentation-with-a-testing-section' into 'master'

Resolve "Extend the "Snowplow event tracking" documentation with a "testing" section"

See merge request gitlab-org/gitlab-ce!25612

Created documentation for replying to comments

See merge request gitlab-org/gitlab-ce!25633

Unquarantine fixed tests

See merge request gitlab-org/gitlab-ee!9915

Unquarantine fixed tests

See merge request gitlab-org/gitlab-ce!25875

Fix "yarn-deduplicate has unmet dependencies"

See merge request gitlab-org/gitlab-ce!25885

Eliminate N+1 queries in Epics API

Closes #10243

See merge request gitlab-org/gitlab-ee!9897

Update burndown chart documentation

Closes #8550

See merge request gitlab-org/gitlab-ee!9896

Fix for mismatch in EE on FIXTURE_PATHS to FIXTURE_PATH

Closes gitlab-ee#10266

See merge request gitlab-org/gitlab-ce!25878

Resolve "Job Failed #173481892"

Closes #10266

See merge request gitlab-org/gitlab-ee!9916

Resolve "Add "No approval required" state to approval rules MR component"

Closes #9963

See merge request gitlab-org/gitlab-ee!9899

Display Ancestors in Issuable Sidebar

See merge request gitlab-org/gitlab-ce!25886

Resolve "Improve stop pipeline modal"

Closes #46464

See merge request gitlab-org/gitlab-ce!25059

Resolve "Project template for iOS"

Closes #58648

See merge request gitlab-org/gitlab-ce!25872