Related issues FE Base

Closes #2001

See merge request !1797

Remove duplicate Project after_validation entry

See merge request !2133

Geo: Fix Dynamic Backoff strategy and add specs

Closes #2639

See merge request !2128

This could be caused by a double request or could have been remoevd by
someone else in another tab

See the previous version of this MR,
https://gitlab.com/gitlab-org/gitlab-ee/merge_requests/1816

Also includes refactoring updates

See https://gitlab.com/gitlab-org/gitlab-ee/merge_requests/1797

Conflicts:
	app/assets/javascripts/issuable/issuable_bundle.js

See https://gitlab.com/gitlab-org/gitlab-ee/merge_requests/1797

See https://gitlab.com/gitlab-org/gitlab-ee/merge_requests/1797

See https://gitlab.com/gitlab-org/gitlab-ee/merge_requests/1797

[EE] Add a custom RSpec/SingleLineHook cop

See merge request !2036

Fix approval spec for project with only one member

See merge request !2117

Clean up Protected branches EE tests, removing unnecessary to_sym usage

Closes #2586

See merge request !2037

This cop adds an offense when `before`, `after`, or `around` are used as
single-line blocks.

See https://gitlab.com/gitlab-org/gitlab-ee/merge_requests/1797

Conflicts:
	app/assets/stylesheets/pages/issues.scss

See https://gitlab.com/gitlab-org/gitlab-ee/merge_requests/1797

See https://gitlab.com/gitlab-org/gitlab-ee/merge_requests/1797

[BE] Related Issues

See merge request !2091

Fix wrong link to codeclimate diff docs

See merge request !2125

Add docs for personal access tokens

See merge request !2127

Handle nil GeoNode to prevent spec failures

See merge request !2124