Extract vibration settings and scaling code from VibratorService

Move the existing logic around vibration settings and ContentObserver to
a separate class, that will be used by VibratiorManagerService once
migration is complete.

Also extract the vibration scaling logic to a separate controller, which
will also be used by the VibratorManagerService after migration.

Bug: 167946816
Bug: 131311651
Test: atest FrameworksServiceTests:VibratorServiceTest
      atest FrameworksServiceTests:VibrationSettingsTest
      atest FrameworksServiceTests:VibrationScaleTest
Change-Id: Idf081e662aa218e93a38cd3262a1357e2e3faf0d