Utilities for managing event listeners from AudioService 2/2

Part 2/2: class to make managing listeners even easier

Add class that leverages the CallbackUtil utility methods
so listener lists, locks and dispatcher stubs don't need
to be members of the class using the new LazyListenerManager
class.
The utility class is used to refactor the management of
the following listeners:
  Spatializer.OnSpatializerStateChangedListener
  Spatializer.OnHeadTrackingModeChangedListener
  AudioManager.OnModeChangedListener
  AudioManager.OnCommunicationDeviceChangedListener

Bug: 206040617
Test: atest AudioModeListenerTest AudioCommunicationDeviceTest \
 SpatializerTest

Change-Id: Ie20c8ff2dddadc2c778c8a9ba4385f28da80e9a6