Implement ability to update deploy keys

What does this MR do?

Implement ability to update deploy keys

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

I suppose so if deploy_key added via admin panel, user should not have ability to rename it (because it will be affected to all users) and Edit button not available for public keys (but admins can rename them via admin panel).

And I didn't update documentation.

Screenshots (if relevant)

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 #3191 (closed)