Brawlstats

Changed
- No longer need to access a players or clubs attribute when getting a leaderboard

Fixed
- Fixed a bug in the sync version of `get_constants()` where there was an extra `await`

Added
- Constants extracted from the Brawl Stars App using `Client.get_constants`

BREAKING CHANGES: Brawl Stars dev team changed "Band" to "Club". This update fixes all of that.
Changed
- `Band` has been changed to `Club`
- `SimpleBand` has been changed to `PartialClub`
- Documentation has been updated for this
- All methods that originally had "band" in them have been changed to "club"
- All attributes that originally had "band" in them have been changed to "club"

Added
- `RateLimitError` to handle the 2 requests/sec ratelimit of the API.

Added
- Remove warnings and stuff to prevent memory leaks and fix session initialization (PR from Kyber)