- Remove abstract captcha manager in favor of a primitive captcha code storage (composition over inheritance)
- Supply player when checking captcha code for further usage (fixes open point from previous commit)
- Checkstyle config: allow todo comments with issue number
- Create consistency tests across all classes, ensuring: unique class names, users of expiring collectors implement HasCleanup, non-private fields are only constants
- Fix tag replacement in PlayerListener for {DISPLAYNAME}