[Meta] Merge Request widget Improvements

Resources

UX @dimitrieh FE @psimyn

Sub Issues

Simplify wording

• https://gitlab.com/gitlab-org/gitlab-ce/issues/32641
• https://gitlab.com/gitlab-org/gitlab-ce/issues/32971
• https://gitlab.com/gitlab-org/gitlab-ce/issues/34387
• https://gitlab.com/gitlab-org/gitlab-ce/issues/33978

Button sizing & spacing

• https://gitlab.com/gitlab-org/gitlab-ce/issues/33087
• https://gitlab.com/gitlab-org/gitlab-ce/issues/33972
• https://gitlab.com/gitlab-org/gitlab-ce/issues/33973
• https://gitlab.com/gitlab-org/gitlab-ce/issues/33974
• https://gitlab.com/gitlab-org/gitlab-ce/issues/33971

Dot points & Tree lines

• Add border lines between sections https://gitlab.com/gitlab-org/gitlab-ce/issues/33976
• Remove tree lines - https://gitlab.com/gitlab-org/gitlab-ce/issues/33982
• Inline Revert / Cherrypick buttons - https://gitlab.com/gitlab-org/gitlab-ce/issues/34253
• Use CI Status icons - https://gitlab.com/gitlab-org/gitlab-ce/issues/32614
• Group items properly - https://gitlab.com/gitlab-org/gitlab-ce/issues/32809

Others

• https://gitlab.com/gitlab-org/gitlab-ce/issues/33965
• https://gitlab.com/gitlab-org/gitlab-ce/issues/33969
• https://gitlab.com/gitlab-org/gitlab-ce/issues/33970
• https://gitlab.com/gitlab-org/gitlab-ce/issues/34255
• https://gitlab.com/gitlab-org/gitlab-ce/issues/33977
• https://gitlab.com/gitlab-org/gitlab-ce/issues/33979
• https://gitlab.com/gitlab-org/gitlab-ee/issues/1126 (planned for 9.5, but perhaps possible to do in 9.4? Is up to you @psimyn )
• https://gitlab.com/gitlab-org/gitlab-ce/issues/34020
• https://gitlab.com/gitlab-org/gitlab-ce/issues/34092
• https://gitlab.com/gitlab-org/gitlab-ce/issues/34540
• https://gitlab.com/gitlab-org/gitlab-ce/issues/34735
• https://gitlab.com/gitlab-org/gitlab-ce/issues/30015