LeAudio: Reafactor data path data structure

This is needed for the codec extensibility and the
new AIDL configuration provider data.

Bug: 340400084
Test: atest bluetooth_le_audio_test bluetooth_le_audio_client_test
Flag: EXEMPT; Refactor for the multi-codec, covered by the unit tests
Change-Id: I16f986f49cb8c53c04071e2d7ae092e54268f444