LeAudio: Clean-up the QoS structures in ASE

Bug: 308427707
Flag: EXEMPT; only grouped the fields into structures - mechanical refactor - correctness confirmed with unit tests
Test: atest --host bluetooth_le_audio_test bluetooth_le_audio_client_test  bluetooth_test_broadcaster bluetooth_test_broadcaster_state_machine bluetooth_le_audio_codec_manager_test --disable-upload-result --minimal-build --no-metrics
Change-Id: I3bbda232fca9da8ea1ba14187568b0e89898ae65