BTA AV CO active device management

Problem: Currently, there can be only one active device in the
BtaAvCo source. This disallows both source and sink device to
be connected simultaneously.

Solution: Introduced new state for source and sink profiles.
Each profile will have their own active device and codec state.
Based on the peer state or the local profile, appropriate
state would be used to access or update the active device.

Test: atest net_bt_*
Bug: 323906246
Bug: 321806163
Change-Id: I137f0f0a8e932b874a7bddaa7e33d4b1dc379abf