SettingsState: Make use of sound effects

settings_slide has also been converted to 44100 Hz for proper playback.
KeyBindingList: Make use of rebinding sounds

SettingsState passes it the Channel required for playing these sounds.

Additionally, settings_remap.wav was replaced with a better sound, and
invalid.wav has its volume lowered slightly.
Only play left/right sfx if SettingList has focus

If back or forward are entered by the players, the list scrolling sound
should only play if the SettingList is currently selected (since
KeyBindingList doesn't have anything to scroll through horizontally).