MR Widget EE Feature branch

This MR includes the EE-only pieces of the MR widget that needed to be revised as part of a complete redesign/refactor of the MR widget.

  • Get tests passing
  • Update Merge Buttons on Unapprove
  • Clean up code
  • Add Geo component
  • Delete old code (approvals, squash button)
  • Add styles

Related: https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/10319