- Fix nth-child selector weirdness in karma tests
- Refactor alert widget tests to use proper waiting instead of
  Vue.nextTick
- Fix modal selector in review bar test
- Fix jest tests by mocking methods correctly
- Adjust event firing for custom dropdown

Also:
- stub MutationObserver in Jest

A recent update in [GitLab UI] and setting the [config.assets.paths] to
include `node_modules` for the resolution of SCSS imports, allows us to
have much nicer imports which don't rely on brittle relative paths.

This change also forwards @gitlab/ui to the newest version

[GitLab UI]: https://gitlab.com/gitlab-org/gitlab-ui/merge_requests/602
[config.assets.paths]: https://gitlab.com/gitlab-org/gitlab-ce/blob/d9026d0ffa0/config/application.rb#L169

Doc backport: Add `/relate` quick action

See merge request gitlab-org/gitlab-ce!29803

Add `/relate` quick action

Closes #6249

See merge request gitlab-org/gitlab-ee!14257

added code difference in `app/views/search/_category.html.haml` from EE to CE

See merge request gitlab-org/gitlab-ce!28755

move EE-specific code to subtemplate

Closes #11039

See merge request gitlab-org/gitlab-ee!14080

CE port of https://gitlab.com/gitlab-org/gitlab-ee/merge_requests/14108

See merge request gitlab-org/gitlab-ce!29604

Support remapping of Git repos via SSH with project aliases

See merge request gitlab-org/gitlab-ee!14108

Set higher TTL to write lock for traces

See merge request gitlab-org/gitlab-ce!30064

Document the security tools maintenance and vulnerabilities DB update

Closes gitlab-ee#9986

See merge request gitlab-org/gitlab-ce!29840

Support CIDR notation in IP rate limiter

See merge request gitlab-org/gitlab-ce!30146

Added commit type to tree GraphQL type

See merge request gitlab-org/gitlab-ce!29412

Extract MR's widget into a separate request

Closes #62723

See merge request gitlab-org/gitlab-ce!29979

Do not change updated_at on an issue when reordering on an issue board

See merge request gitlab-org/gitlab-ce!29677

Fix weight quick action to support 0 value

Closes #10324

See merge request gitlab-org/gitlab-ee!14432

Backport CE changes for multiple GroupSAML support

See merge request gitlab-org/gitlab-ce!30102

Fix handling of multiple GroupSAML identities

Closes #12303

See merge request gitlab-org/gitlab-ee!14420

Resolve "Environment details header border misaligned"

Closes #62968

See merge request gitlab-org/gitlab-ce!30011

Show position of merge trains in system notes

Closes #12265

See merge request gitlab-org/gitlab-ee!14398

CE backport for gitlab-org/gitlab-ee!11859: Update description text of "Merge requests" section of general project settings page

See merge request gitlab-org/gitlab-ce!27838

Update description text of "Merge requests" section of general project settings page

Closes #11098

See merge request gitlab-org/gitlab-ee!11859

Removes EE differences for app/views/projects/tree/_tree_header.html.haml

See merge request gitlab-org/gitlab-ce!30117

EE port of Removes EE differences for app/views/projects/tree/_tree_header.html.haml

See merge request gitlab-org/gitlab-ee!14433

Edit Cluster Admin note text

Closes #63558

See merge request gitlab-org/gitlab-ce!29965