Merge branch '4506-spec-failure-in-spec-ee-spec-services-ee-projects-hashed_storage-migrate_repository_service_spec-rb' into 'master'

Resolve "Spec failure in spec/ee/spec/services/ee/projects/hashed_storage/migrate_repository_service_spec.rb"

Closes #4506

See merge request gitlab-org/gitlab-ee!3966

`provider` is always required - remove confusing text

See merge request gitlab-org/gitlab-ee!3889

Running this after
spec/services/projects/hashed_storage/migrate_repository_service_spec.rb would fail
previously, because the new repository path already existed on disk. As this spec expects
the new repository path to not exist on disk prior to being moved, we should clear out
the test repos before running.

Recommend against the use of EFS

See merge request gitlab-org/gitlab-ee!3897

EE changes after moving fast authorized_keys feature to CE

See merge request gitlab-org/gitlab-ee!3959

The spec for "#add_key does nothing" would always have passed,
since the expectation was on both the wrong object and message.

Geo admin screen enhancements

Closes #4268, #4179, and #1363

See merge request gitlab-org/gitlab-ee!3902

EE: Run background migrations with a minimum interval

Closes gitlab-ce#41624

See merge request gitlab-org/gitlab-ee!3933