leaudio: Add BAP and CSIP integration along with audio path

LE Audio implements PAC handling, device grouping into sets,
audio policy by the content type, group stream management,
broadcast etc.
Devices are always part of the group which creates sets.
Sets can be managed by the LeAudio system service which has an API to add/remove
specific devices to/from the group.

Any stream operations are done by the LeAudio system service
with a usage of the group_id.

Note, this group_id is not the same number as the CIG_ID however,
we might say it has the same meaning.

When devices are part of a coordinated set (CSIS), then LeAudio
implementation will discover all of them and notify upper layer about them.
Upper layers are to decide to bond CSIS devices. Native code will
group them.

Fluoride also integrates Android Audio 2.1 framework and once stream is
established then Le Audio session is opened and ready to receive
periodically (up to implementation) audio data from media server
(16bit, 16kHz/24kHz/32kHz/48kHz PCM - up to policy implementation) from
the audio system.

PCM frames are encoded by LC3 codec (system/bt/embdrv/lc3) and pushed over HCI to the
controller.

Bug: 150670922
Tag: #feature
Sponsor: jpawlowski@
Test: atest --host bluetooth_le_audio_test bluetooth_le_audio_client_test

Change-Id: I25d9422fb2b43843a59a9e398fac1e09c7e4869c