audio: Add AudioOffloadMetadata and a method to update it

AudioOffloadMetadata contains the same information
as 'AUDIO_OFFLOAD_CODEC_*' framework parameters.
It is updated via a new method IStreamOut.updateOffloadMetadata
which only works for compressed offload streams.

Bug: 270731693
Test: atest VtsHalAudioCoreTargetTest
Change-Id: I6c8a8853f216438284082f79e3f57e511a2a1f06