Refactor AudioPolicyManager

AudioPolicyManager implementation is now split into the
following files:

files managerdefault/Gains.*
  class AudioGain
  class VolumeCurvePoint
  class StreamDescriptor

files managerdefault/Devices.*
  class DeviceDescriptor
  class DeviceVector

files managerdefault/Ports.*
  class AudioPort
  class AudioPortConfig
  class AudioPatch

files managerdefault/IOProfile.*
  class IOProfile

files managerdefault/HwModule.*
  class HwModule

files managerdefault/AudioInputDescriptor.*
  class AudioInputDescriptor

files managerdefault/AudioOutputDescriptor.*
  class AudioOutputDescriptor

All files for libaudiopolicyservice are moved under service/

All files for libaudiopolicymanager are moved under manager/

Change-Id: I43758be1894e37d34db194b51a19ae24461e066e