Refactor and implement mention inspector


Refactor and implement mention inspector

  • Refactor to add a target (inheriting from sa); this allows customizing the toolbar. It is now limited to three items, plus the menu.
  • Simplify module handling. The main module is still lazy loaded, and that just uses normal dependencies.

    Also, dropped handling the experimental flag for now. Most of the experiments would probably not be applicable, and this is still experimental itself.
  • Implement the initial inspector, with:
    • Toolbar item
    • Auto-complete based on topic authors (case-insensitive, anywhere in the string)
    • Full edit and remove support (for remove, both via back-spacing and by button)
    • Validation that user exists, with appropriate error messages if not.

Depends on:

Bug: T90764
Bug: T92588
Change-Id: I0a14f4779c73996d4cb063b27f3330def0baae6d