WIP: Vueify image diff

What does this MR do?

Convert image diff to use Vue as a first step towards https://gitlab.com/gitlab-org/gitlab-ce/issues/35873 This also fixes several existing bugs with current image diffs

• This MR consistently loads the 2-up view correctly by default (#32613 (closed))
• This MR fixes the alignment issue for swipe frame (#37928 (closed))

Are there points in the code the reviewer needs to double check?

Make sure everything is 💯

Why was this MR needed?

Related to Deliverable

Screenshots (if relevant)

Before (Inconsistent 2-up)	After (Inconsistent 2-up)

Before (Swipe frame)	After (Swipe frame)

Does this MR meet the acceptance criteria?

• Changelog entry added, if necessary
• Documentation created/updated
• API support added
• Tests added for this feature/bug
• 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

What are the relevant issue numbers?

https://gitlab.com/gitlab-org/gitlab-ce/issues/35873, Closes https://gitlab.com/gitlab-org/gitlab-ce/issues/32613, Closes https://gitlab.com/gitlab-org/gitlab-ce/issues/37928