Pipelines Vue

What does this MR do?

This MR is foundation to having realtime pipelines working in Vue.js.

Currently the realtime aspects are blocked by the realtime diff updates on the backend. This will be handled in a different merge request once this one is merged.

Initial API will be finished and this will replace the current pipeline index page.

This is a complete rewrite of the index pipeline tab in Vue.js

@fatihacet @mikegreiling

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

Why was this MR needed?

Screenshots (if relevant)

Does this MR meet the acceptance criteria?

• CHANGELOG entry added
• Documentation created/updated
• API support added
• Tests
  • Added for this feature/bug
  • All builds are passing
• Conform by the merge request performance guides
• Conform by the style guides
• Branch has no merge conflicts with master (if it does - rebase it please)
• Squashed related commits together

What are the relevant issue numbers?

#5983 (closed)