AudioService: new interface for absolute volume control

New class VolumeInfo to communicate any type of
  volume information, such as volume type (stream
  type vs volume group), index and associated
  range.
New manager class AudioDeviceVolumeManager to
  serve as the client-side code for setting
  absolute volume for a given device, and
  registering the corresponding volume change
  listener. This is not done through AudioManager
  so as to not keep on piling functionality
  into it that increases its memory footprint.

Bug: 201781907
Test: upcoming after hook up in AudioService

Change-Id: I97fd1827f27f55a90d92c538c142a4d9aae966b3