This migration can take a bit of time to complete and I don't want to
delay the deployment process.

Additionally we're delegating missing method calls on GpgKeySubkey to
GpgKey since most of the info required when verifying a signature is
found on GpgKey which is the parent of GpgKeySubkey

The content returned by #key is important when veryfying the signature,
so given we don't want to repeat it in the database for GPG subkeys we
need to delegate it to the parent.

Minor backport from EE

See merge request gitlab-org/gitlab-ce!14705

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