Resolve "Show CI pipeline status in Web IDE"

What does this MR do?

Adds the pipeline status of the last commit on the current branch and project to the Status bar of the WebIDE.

It also polls the status on every X seconds, as indicated by the backend (currently 10sec).

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

The polling was the trickiest part to get done. Please have a look there.

Screenshots (if relevant)

(updated May 22nd)

Does this MR meet the acceptance criteria?

• Changelog entry added, if necessary
• API support added (added a call to the api.js)
• Tests added for this feature/bug
• Conform by the code review guidelines
  • Has been reviewed by a UX Designer
  • Has been reviewed by a Frontend maintainer
• Conform by the merge request performance guides
• Conform by the style guides
• If you have multiple commits, please combine them into a few logically organized commits by squashing them
• Internationalization required/considered

What are the relevant issue numbers?

Closes #44579 (closed)