Add config overlay for alarms improvement features in multiuser

By default the features are enabled but can be disabled by overriding their values in corresponding overlay file.

Bug: 385341949
Test: atest UserManagerServiceTest && atest VibratorManagerServiceTest && atest AlarmManagerServiceTest // with config values both on and off
Flag: android.multiuser.multiple_alarm_notifications_support
Change-Id: Ibfdd4d30920bdbef4a3ff1ec177ce8042f403d5d