Add method for creating foreign keys concurrently

See merge request !9069

Rename Files::DeleteService to Files::DestroyService

See merge request !9110

Resolve "Improve blockquote formatting in notification emails"

Closes #28029

See merge request !9157

Convert some vendored javascript assets to npm modules

See merge request !8990

fixes MR widget jump

Closes #27994

See merge request !9146

* master: (26 commits)
  Revert "Merge branch 'add-additional-checks-to-ca-data' into 'master'"
  Fix broken test to use trigger in order to not take tooltip overlaping in consideration
  Fix job to pipeline renaming
  Added env external link and light web terminal spec
  Don't perform Devise trackable updates on blocked User records
  Replace teaspoon references with Karma
  Add changelog
  Only show MR widget graph if there are stages
  Remove orange caret icon from mr widget
  Add index to ci_trigger_requests for commit_id
  rspec_profiling: Discover the correct branch name in GitLab CI
  Show parent group members for nested group
  Fix tooltip scss for anchors. Adds css for button's tooltips to have similar behavior. Removes padding from mini graph table cell to guarantee stages don't break line on hover
  Updated protected branches dropdown image in docs
  Fix admin_labels_spec.rb transient failure
  Make sure events have most properties defined
  Restore exposure of legend property for events
  moved hyperlink reference section at the end of the content
  Make sure our current .gitlab-ci.yml is valid
  adds changelog
  ...

Remove fixed positioning from navbar

See merge request !7547

This adds a Rubocop rule to enforce the use of
add_concurrent_foreign_key instead of the regular add_foreign_key
method. This cop has been disabled for existing migrations so we don't
need to change those.

This method allows one to create foreign keys without blocking access to
the source table, but only on PostgreSQL.

When creating a regular foreign key the "ALTER TABLE" statement used for
this won't return until all data has been validated. This statement in
turn will acquire a lock on the source table. As a result this lock can
be held for quite a long amount of time, depending on the number of rows
and system load.

By breaking up the foreign key creation process in two steps (creation,
and validation) we can reduce the amount of locking to a minimum.
Locking is still necessary for the "ALTER TABLE" statement that adds the
constraint, but this is a fast process and so will only block access for
a few milliseconds.

Only show MR widget graph if there are stages

Closes #27987

See merge request !9141

Replace teaspoon references with Karma

Closes gitlab-com/gitlab-docs#68

See merge request !9011

fixes frontend doc broken link

Closes #27783

See merge request !9120

Revert "Merge branch 'add-additional-checks-to-ca-data' into 'master'"

See merge request !9152

This reverts commit b7c5ca49, reversing
changes made to 9745c98b.

Fixes tooltips in mini pipeline graph

Closes #27963 and #28008

See merge request !9140

Fix job to pipeline renaming

Closes #28016

See merge request !9147