Add support for dual (co-op) mode in mania beatmap
Ensure all OsuFocusedOverlayContainers contribute to screen fading
Fix song select blur potentially never being applied
Add UserID for databased scores where possible
Only display SupportedWindowModes in settings
# Conflicts: # osu.Game/Screens/Select/SongSelect.cs
Move user dim logic into new UserDimContainer
Refactor BeatmapSetOverlay to use chained bindables
Fix race condition during game load + disposal
Conditionally add some UI elements only on desktop