Refresh open Issue and Merge Request project counter caches when re-opening

Closes #39583

See merge request gitlab-org/gitlab-ce!15085

Fix broken Members link when relative URL root paths are used

See merge request gitlab-org/gitlab-ce!15070

Resolve "Performance bar appears enabled even though it won't show up"

Closes #39570

See merge request gitlab-org/gitlab-ce!15084

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

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

Remove code from global namespace

See merge request gitlab-org/gitlab-ce!15058

Update i18n in FE docs for marking and interpolation

See merge request gitlab-org/gitlab-ce!15020

Fix call stack size exceeded group milestone description autocomplete

Closes #39020

See merge request gitlab-org/gitlab-ce!14972

Merge branch 'pawel/bump_prometheus_gem_to_fix_read_all_values_returning_bad_data-39504' into 'master'

Update Prometheus Gem to fix problem caused by using wrong data offsets

See merge request gitlab-org/gitlab-ce!15081

Changed project select to use it independently and not onlt as a combobutton

See merge request gitlab-org/gitlab-ce!15043

Fix 500 error for old (somewhat) MRs

Closes #36540

See merge request gitlab-org/gitlab-ce!14945

Upgrade Gitaly to v0.50.0

See merge request gitlab-org/gitlab-ce!15050

Merge branch '39054-activerecord-statementinvalid-pg-querycanceled-error-canceling-statement-due-to-statement-timeout' into 'master'

Resolve "ActiveRecord::StatementInvalid: PG::QueryCanceled: ERROR:  canceling statement due to statement timeout"

Closes #39054

See merge request gitlab-org/gitlab-ce!15063

Add docs for backing up to Google Cloud Storage

See merge request gitlab-org/gitlab-ce!15074

Add missing circuitbreaker metrics to prometheus documentation

See merge request gitlab-org/gitlab-ce!15062

* master: (51 commits)
  Move locked check to a guard-clause
  Ci::Build tag is a trait instead of an own factory
  [CE backport] Saved configuration for issue board
  Use the correct project visibility in system hooks
  Add changelog
  more readable changelog
  Make merge_jid handling less stateful in MergeService
  Fetch the merged branches at once
  remove extra whitespace
  use a delegate for `username` to be more future friendly
  Merging EE doc into CE
  add changelog entry
  Avoid using Rugged in Gitlab::Git::Wiki#preview_slug
  Cache commits on the repository model
  Remove groups_select from global namespace & simplifies the code
  Change default disabled merge request widget message to "Merge is not allowed yet"
  Semi-linear history merge is now available in CE.
  Remove repetitive karma spec
  Improve spec to check hidden component
  Rename to shouldShowUsername
  ...

Ci::Build tag is a trait instead of an own factory

See merge request gitlab-org/gitlab-ce!15077

Fix widget of locked merge requests not being presented

See merge request gitlab-org/gitlab-ce!15069

Minor annoyance of mine, and there were a couple of things wrong, for
example:
1. Switching on a property is just a trait
2. It didn't inherrit from its parent

Find and replace through the code based fixed all occurances.

[CE backport] Saved configuration for issue board

See merge request gitlab-org/gitlab-ce!15009

Use the correct project visibility in system hooks

Closes #39496

See merge request gitlab-org/gitlab-ce!15065

grab the correct username when confirming secondary email

Closes #39366

See merge request gitlab-org/gitlab-ce!15010

Remove Autosave class from global namespace

See merge request gitlab-org/gitlab-ce!14856

Update docs on creating MRs

See merge request gitlab-org/gitlab-ce!14982

Navigating to the "Members" section of a project would omit the
relative URL root path. Fix the redirection and eliminate the
need for a redirection in the first place.

Fix other redirections failing to work with relative roots

Fetch the merged branches at once.

Checking it one by one in the view. We don't cache this yet
because this would already much improve the performance.

A naive test against a particularly large repository:

``` ruby
begin
  now = Time.now
  branches.map{ |b| r.merged_to_root_ref?(b.name) }
  Time.now - now
end # 8.265830782
```

Around 10 times faster:

``` ruby
begin
  now = Time.now
  r.merged_branches(branches.map(&:name))
  Time.now - now
end # 0.807405397
```

This should make the branches page usable.

See merge request gitlab-org/gitlab-ce!14729