EE - Remove groups_select from global namespace & simplifies the code

See merge request gitlab-org/gitlab-ee!3203

Change default disabled merge request widget message to be more general -- EE merge edition

Closes gitlab-ce#39188

See merge request gitlab-org/gitlab-ee!3180

Revert "Merge branch '36670-remove-edit-form' into 'master'"

See merge request gitlab-org/gitlab-ee!3208

* master: (139 commits)
  btn-small -> btn-sm
  Merge branch 'fix-application-setting-nil-cache' into 'master'
  no CI replication
  [CE->EE] Resove frontent conflicts
  [CE->EE] Fix wrong resolvation of specs
  [CE->EE] Resolve group routes
  [CE->EE][ci skip] Resolve conflicts
  Resolve conflict in lib/backup/manager.rb
  Resolve conflict in .gitlab-ci.yml
  [CE->EE][ci skip] Resolve conflicts
  [CE->EE][ci skip] resolve frontend conflicts
  Remove `<script>` and `<template>` from CHANGELOG.md
  Simple docs fixes
  Fix button type
  Changes after review
  Removes group_avatar & group_label_subscription from global namespace
  Fix CSS in load more participants
  Fix the description of the new branch created by an issue's new branch button
  Fix a small typo in the delete merged branches documentation
  Moves vue resource docs into a new file. Adds docs regarding handling 204 response
  ...

Fix https://gitlab.com/gitlab-org/gitlab-ce/issues/39188

btn-small -> btn-sm

Closes #3637

See merge request gitlab-org/gitlab-ee!3210

This reverts commit 915e35a2, reversing
changes made to 9533786f.

CE upstream

Closes #3794, #3781, gitaly#638, and gitlab-ce#38923

See merge request gitlab-org/gitlab-ee!3199

Prevent ApplicationSetting to cache nil value

Closes #39275

See merge request gitlab-org/gitlab-ce!14952

no CI replication

See merge request gitlab-org/gitlab-ee!3192

* master: (33 commits)
  Changing the smallest of typos
  Remove `<script>` and `<template>` from CHANGELOG.md
  Fix icon color and btn-group alignment of discussion buttons
  Simple docs fixes
  Fix button type
  Changes after review
  fixed karma tests
  Removes group_avatar & group_label_subscription from global namespace
  Fix CSS in load more participants
  Fix the description of the new branch created by an issue's new branch button
  Fix a small typo in the delete merged branches documentation
  spec fixes
  Remove Sherlock usage from the performance bar
  moved to eventHub to manage creating new files removed an ID from the CSS
  Use the new buttons for creating groups and projects in QA tests
  fixed eslint 🙈
  added feature spec
  fixed failing title test
  fixed bug with tabs not switching correctly
  failing spec fixes
  ...

Signed-off-by: Rémy Coutable <remy@rymai.me>

Signed-off-by: Rémy Coutable <remy@rymai.me>

Add note about coming group milestone support

See merge request gitlab-org/gitlab-ee!3195

(EE-Port) Circuitbreaker backoff and retries

See merge request gitlab-org/gitlab-ee!3191

Remove problematic H1 from alpha_database.md

See merge request gitlab-org/gitlab-ee!3201

Simplify Geo installation docs: tracking DB is enabled by default now

Closes #3827

See merge request gitlab-org/gitlab-ee!3200

EE- remove new sidebar stuff

See merge request gitlab-org/gitlab-ee!3197

Port of "Remove Autosave class from global namespace" to EE

See merge request gitlab-org/gitlab-ee!3198

Closes #3827

[ci skip]

Rename the Alpha PG HA documentation to just the PG HA documentation

See merge request gitlab-org/gitlab-ee!3151