Fix distance snap grid not properly working due to multiple issues
Implement visual appearance of beatmap submission wizard
Implement "form button" control
Add group support to beatmap carousel v2
Only used in test code.
IDistanceSnapProvider
Method signatures are also changed to be a lot more explicit as to what inputs they expect.
Make offset adjust more lenient
GameplayStartTime
IGameplayClock
Where possible I've tried to match the test and method names of `TestSceneBeatmapCarousel` for easy coverage comparison.
CarouselItem
sealed
BeatmapCarouselItem
Less abstraction is better. As far as I can tell, we don't need a custom model for this. If there's any tracking to be done, it should be done within `BeatmapCarousel`'s implementation (or a filter).