Convenient use of concurrent migration helpers

Closes #43887

See merge request gitlab-org/gitlab-ce!17888

NestingDepth (level 5) in framework/dropdowns.scss

See merge request gitlab-org/gitlab-ce!17820

Changes empty project avatar to identicon in the IDE

Closes #44298

See merge request gitlab-org/gitlab-ce!17899

Refactor ConfirmDangerModal into ES module

See merge request gitlab-org/gitlab-ce!17874

Update licensee 8.7.0 -> 8.9

Closes #18077

See merge request gitlab-org/gitlab-ce!17719

Closes #44298

Update gettext_i18n_rails_js 1.2.0 -> 1.3

See merge request gitlab-org/gitlab-ce!17801

Move IDE to CE

Closes #44157

See merge request gitlab-org/gitlab-ce!17887

Strip any query string parameters from Location headers from lograge

See merge request gitlab-org/gitlab-ce!17895

Port of https://github.com/roidrage/lograge/pull/241

Add performance monitoring docs for the new FE guide

See merge request gitlab-org/gitlab-ce!17809

Update spec import path for vue mount component helper

See merge request gitlab-org/gitlab-ce!17880

Closes #43887.

Index creation does not have an effect if the index is present already.
Index removal does not have an affect if the index is not present.

This helps to avoid patterns like this in migrations:
```
if index_exists?(...)
  remove_concurrent_index(...)
end
```

Resolve "Loss of input text on comments after preview"

Closes #42880

See merge request gitlab-org/gitlab-ce!17076

Prevent auto-retry AccessDenied error from stopping transition to failed

See merge request gitlab-org/gitlab-ce!17862

Fix end-to-end specs for rebasing a merge request

Closes gitlab-qa#208

See merge request gitlab-org/gitlab-ce!17885

Update merge request maintainer access docs

See merge request gitlab-org/gitlab-ce!17864

This also makes the IDE generally available

Update cloud native Helm chart docs for alpha

See merge request gitlab-org/gitlab-ce!17875

Resolve "Add documentation for "Display IP Address Of Runner On Runner Page""

Closes #44232

See merge request gitlab-org/gitlab-ce!17837

Update rack-protection to 2.0.1

Closes #44388

See merge request gitlab-org/gitlab-ce!17835

Use update_column than write_attribute and save

Closes #44366

See merge request gitlab-org/gitlab-ce!17861

Resolve "Prometheus graphs have no empty state when no data is present"

Closes #42558

See merge request gitlab-org/gitlab-ce!17759

Resolve "Search code blob sometimes shows filename and branch"

Closes #44280

See merge request gitlab-org/gitlab-ce!17777