hal: Add support to enable A2DP offload

- Add new audio extension module for a2dp
- Add support to configure AFE encoder based
  on BT device capabilities
- Add support for soft handoff to re-configure
  AFE based on new BT device capability

Bug: 63932139
Bug: 68824150
Test: A2DP offload verified on supported codecs
Change-Id: Idede77276d2be99fa7e7400495248fe2e63eecf5
(cherry picked from commit fca405d5)