Resolve "Allow to disable username on checkout url"

What does this MR do?

This reverts !9347 (merged) and (partially) reverts !10079 (merged) to not allow Project#http_url_to_repo nor ProjectWiki#http_url_to_repo to take a user.

Why was this MR needed?

Because this feature is causing more harm than good.

Does this MR meet the acceptance criteria?

• Changelog entry added, if necessary
• 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?

Closes #30410 (closed) and #30174 (closed)