Add difficulty adjustment settings to editor setup screen
Add editor beatmap batch change support
Fix HitWindows getting serialized alongside HitObjects
These were being serialized as the base type. On deserialization, due to the HitWindow of objects being non-null, they would not get correctly initialised by the CreateHitWindows() virtual method. - Closes #10403
# Conflicts: # osu.Game/Overlays/Settings/Sections/Input/MouseSettings.cs
Fix incorrect sliderendcircle fallback logic
Split editor setup screen up into sections
Add repeats display to timeline blueprints
Make stacked hitcircles more visible when using default skin
Add obsoleted Bindable property back to SettingsItem for compatibility
Increase backwards seek magnitude when the track is running
Seek at 4x normal speed when holding shift (not 2x)