Merge changes I5719d43c,Ia756d0fa,Iba08e90a,Ia5d1b195,I678011f4, ...

* changes:
  Replace unreadable AG state machine
  good riddance AV stream state machine
  Replace AV non state machine function table
  Replace BTA AV state machine
  Flatten bta_hd_sm_execute
  Remove unused parameter from bta_hd_vc_unplug_act
  Remove unused parameter from bta_hd_disconnect_act
  Remove unused parameter from bta_hd_unregister_act
  Replace unreadable HD state machine
  Replace HH unreadable state machine
  BTA_HH_LE_INCLUDED is always true
  Remove unreferenced mce file & headers
  btif_mce_get_interface is never called
  Callbacks are never used
  Remove MCE code that now no longer does anything
  BTA_MceGetRemoteMasInstances does nothing
  bta_mce_get_remote_mas_instances is never referenced
  bta_mce_enable is never referenced
  bta_mce_sm_execute is never referenced
  Remove now unused BTA_MceEnable
  btif_mce_execute_service is never called
  booleans are a thing for a reason
  Simplify BTA_SdpCreate/RemoveRecordByUser
  Simplfy BTA_SdpSearch
  simplify BTA_SdpEnable
  Burninate SDP "state machine"