Add repository languages for projects

What does this MR do?

Adds a bar to the project page displaying the languages the repository consists off.

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

Frontend stuff, plus the performance impact.

Why was this MR needed?

Our friends over at GitHub got this right, I feel. I've been missing this feature since I've started using GitLab. I'm aware of the previous shot at this. Key difference is that gitaly!751 (closed) will make this much more bearable for our infrastructure.

Screenshots

If there's no detection yet, nothing changes. If there is:

Does this MR meet the acceptance criteria?

• Changelog entry added, if necessary
• Documentation created/updated
• API support added
• Tests added for this feature/bug
• Conform by the code review guidelines
  • Has been reviewed by a UX Designer (@dimitrieh, could you do this?)
  • Has been reviewed by a Frontend maintainer
  • Has been reviewed by a Backend maintainer
  • Has been reviewed by a Database specialist
• Internationalization required/considered
• End-to-end tests pass (package-and-qa manual pipeline job)

What are the relevant issue numbers?

Closes https://gitlab.com/gitlab-org/gitlab-ce/issues/23931

Closes https://gitlab.com/gitlab-org/gitlab-ce/issues/34671

Closes #48647 (closed)

En passant, this closes https://gitlab.com/gitlab-org/gitlab-ce/issues/47301