Drop unused helpers and associated specs

What does this MR do?

This MR deletes unused helper methods and their associated specs. I delete each method on its own commit so that it's easy to revert in case we need that. We can squash the history together later if you think that's better.

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

Some methods might be called using meta programming, in a way that ag wouldn't catch. I hope the extensive test suite takes care of that, and that domain knowledge by reviewers does too.

Why was this MR needed?

The Best Code is No Code At All.

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 you do - rebase it please)
• Squashed related commits together