leaudio: Rework selecting Broadcast Audio stream parameters

This change adds support for broadcast audio stream
parameter slection through the stream context type
in the metadata stream parameter. The passed context
is being mapped to a specific set of lc3 codec
paremeters and QOS settings.

Proper QOS settings were the missing piece for a while
now in the broadcast audio source implementation, and
this change fixes these outstanding todos. This change
is also needed to pass some of qualification tests for
BAP Broadcast Source.

Bug: 230340466
Tag: #feature
Sponsor: jpawlowski@
Test: atest LeAudioBroadcastServiceTest bluetooth_test_broadcaster_sm bluetooth_test_broadcaster
Change-Id: I5f6c2ceca4120f65bdfd51fcde6c9c3802bf02e9
Merged-In: I5f6c2ceca4120f65bdfd51fcde6c9c3802bf02e9
(cherry picked from commit af290f42)