This is based on:

https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/10841

* upstream/master: (109 commits)
  Update CI templates to include 9.1 templates
  Change spec folder to match the assets one
  Update style_guide_js.md
  Milestones documentation refactor
  Adds documentation entry: Don't user forEach, aim for code without side effects
  Move kube namespace section to the variables one
  Changed milestone.to_reference calls into milestone.title for the show, edit and top views
  Update move icon to match others
  Issue Title Show Focus Check On Load
  Update Kubernetes namespace documentation
  Store projects in metrics for email replies
  Refactor into .vue files
  Adds vue js example application and documentation
  Add ES lint support to identify poorly written Promises
  Update plantuml.md to add the actual link.
  Fixed wording
  Add metrics events for incoming emails
  Remove helpers assigned_issuables_count and cached_assigned_issuables_count
  Refactor into .vue files part 2
  Fix headings
  ...

Change spec folder to match the assets one

See merge request !10834

Closes #31215

Update CI templates to include 9.1 templates

See merge request !10807

Add parameter limit to styleguide

See merge request !10830

Don't run the downtime check on stable branches, or tags/master

See merge request !10794

Kubernetes service namespace

Closes #30445

See merge request !10821

Milestones documentation refactor

See merge request !10812

Adds documentation entry: Don't user forEach, aim for code without side effects

See merge request !10811

Update move icon to match others

Closes #31116

See merge request !10790

Changed milestone.to_reference calls into milestone.title for the show, edit and top views

See merge request !10637

Docs tech articles filetree

Closes #30946

See merge request !10752

Refactor code that creates and destroys project/group members

See merge request !10735

Add email receiver metrics

See merge request !10814

Issue Title Show Focus Check On Load

See merge request !10800

Unassign all Issues and Merge Requests when member leaves a team

Closes #30768 and #24117

See merge request !10755

Update plantuml.md to fix wrong introduced in link.

Closes #31154

See merge request !10806

Refactor into .vue files

See merge request !10788

Add documentation for inactive users in the User cohort

Closes #31195

See merge request !10809

Adds vue js example application and documentation

Closes #30031 and #30030

See merge request !10693

Add ES lint support to identify poorly written Promises

See merge request !9969

Port of fix/29125-ee to CE

Closes #29125

See merge request !10796

This lets us track how many incoming emails a GitLab instance is processing, by
email type (handler) and by project (where applicable).