Send a confirmation email when the user adds a secondary email address

Closes #37385, #28621, and #36959

See merge request gitlab-org/gitlab-ce!14703

Only add identities to a user if we find one in Gitlab::OAuth::User.

Closes #38801

See merge request gitlab-org/gitlab-ce!14702

Update github.md importer docs to clarify branches from forks get created in GL

See merge request gitlab-org/gitlab-ce!14670

# Conflicts:
#	app/controllers/admin/users_controller.rb
#	app/controllers/confirmations_controller.rb
#	app/controllers/profiles/emails_controller.rb
#	app/models/user.rb
#	app/services/emails/base_service.rb
#	app/services/emails/destroy_service.rb
#	app/views/devise/mailer/confirmation_instructions.html.haml
#	lib/api/users.rb
#	spec/services/emails/destroy_service_spec.rb

Resolve "Monitoring hover info is clipped"

Closes #38031

See merge request gitlab-org/gitlab-ce!14514

Fixes group milestones breadcrumb links

Closes #38781

See merge request gitlab-org/gitlab-ce!14689

Use the default password from the GDK's root user

Closes gitlab-qa#73

See merge request gitlab-org/gitlab-ce!14701

Use simple path for tmp ref, avoiding extra directory

See merge request gitlab-org/gitlab-ce!14698

[ci skip]

Speed up DeclarativePolicy::Runner#steps_by_score

See merge request gitlab-org/gitlab-ce!14679

Update QA Nokogiri to 1.8.1

See merge request gitlab-org/gitlab-ce!14700

Resolve "Prometheus graphs occasionally have incorrect Y scale"

Closes #38789

See merge request gitlab-org/gitlab-ce!14693

Resolves three security advisories from bundle-audit

Remove 'Repo' prefix from API entities

Closes #28417

See merge request gitlab-org/gitlab-ce!14694

So that we don't have to worry about cleaning empty
directories later. This was brought up at:

https://gitlab.com/gitlab-org/gitlab-ce/issues/38689#note_42242988

Both `Or` and `And` would evaluate whether each rule passed, then calculate a
value based on the results of all of those. We can actually return early in many
cases, without running the rule at all.

Resolve "Hover and legend data should be linked"

Closes #38036

See merge request gitlab-org/gitlab-ce!14400

[ci skip]

Merge branch '37111-monitoring-graph-empty-states-are-gigantic-on-screen-sm-viewport-sizes' into 'master'

Resolve "Monitoring graph empty states are gigantic on `screen-sm` viewport sizes"

Closes #37111

See merge request gitlab-org/gitlab-ce!14259

Clarify where the artifacts metadata .gz is generated

See merge request gitlab-org/gitlab-ce!14695

Fix inconsistent use of sentence case

See merge request gitlab-org/gitlab-ce!14668

Fix username and ID not logging in production_json.log for Git activity

Closes gitlab-ee#3611

See merge request gitlab-org/gitlab-ce!14647

improve merge request widget status icon UX

Closes #37229

See merge request gitlab-org/gitlab-ce!14200

[ci skip]

Closes #38781

Cleanup Select2 dropdown styles

Closes #37279

See merge request gitlab-org/gitlab-ce!14557

Makes `@mentions links` have a different styling for better separation

See merge request gitlab-org/gitlab-ce!14377