(Part 7) FE multiple approval rules - mr widget

What does this MR do?

This MR is part of !9001 (merged) which updates the MR widget to support multiple approval rules.

To run locally, enable the approval_rules and multiple_approval_rules flag.

Instructions!

This contains commits labeled CE:. These CE MR's should be merged first, and these commits rebased out of here.

• https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/24875

Screenshots

Demo	Responsive

No rules	Code owners + no rules

note: Check icon has been updated to mobile-issue-close

What are the relevant issue numbers?

Part of #1979 (closed)

Part of https://gitlab.com/gitlab-org/gitlab-ee/issues/8350 (FE)

Does this MR meet the acceptance criteria?

• Changelog entry added, if necessary
• Documentation created/updated via this MR
• Documentation reviewed by technical writer or follow-up review issue created
• Tests added for this feature/bug
• Tested in all supported browsers
• Conforms to the code review guidelines
• Conforms to the merge request performance guidelines
• Conforms to the style guides
• Conforms to the database guides
• Link to e2e tests MR added if this MR has Requires e2e tests label. See the Test Planning Process.
• EE specific content should be in the top level /ee folder
• For a paid feature, have we considered GitLab.com plans, how it works for groups, and is there a design for promoting it to users who aren't on the correct plan?
• Security reports checked/validated by reviewer