Implement ability to update hooks

What does this MR do?

Implement ability to edit ProjectHook and SystemHook via UI.

This MR needed for #17848 (closed) and #5971 (closed)

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

Now index and edit pages for user (project_hooks) and admin (system_hooks) looks totally different. Perhaps we need to bring them to similar view?

I am not sure in validity of form on edit page (now it looks the same as index form).

Screenshots

Does this MR meet the acceptance criteria?

• Changelog entry added, if necessary
• Documentation created/updated
• [ ] API support added (looks like update functionality already exists)
• 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 #19364 (closed)