Moves .js components in mr widget into vue files

What does this MR do?

1. Moves .js vue components into .vue files
2. Adds i18n
3. Cleans up tests

Does this MR meet the acceptance criteria?

• Review
  • Has been reviewed by UX
  • Has been reviewed by Frontend
  • Has been reviewed by Backend
  • Has been reviewed by Database
• Conform by the merge request performance guides
• Conform by the style guides
• Squashed related commits together
• Internationalization required/considered
• End-to-end tests pass (package-qa manual pipeline job)

What are the relevant issue numbers?

https://gitlab.com/gitlab-org/gitlab-ce/issues/41582 https://gitlab.com/gitlab-org/gitlab-ce/issues/34371