floss: Pass BluetoothAudioDevice as a dictionary

This change involves
- Uses BluetoothAudioDevice instead of separated field
  OnBluetoothAudioDeviceAdded signal.
- Attaches all A2dpCodecConfig instead of only the SBC one. This enables
  the capability for clients to choose which a2dp codec config to use.
- Implements a impl_dbus_arg_from_into macro for bitflags and other
  structs to implement DBusArg based on TryFrom and TryInto.

Tag: #floss
Bug: 192351068
Test: build, deploy, connect and check the dbus_monitor output.
BYPASS_LONG_LINES_REASON: Bluetooth likes 120 char lines

Change-Id: I20842ea09f3d7b3619504d72b4bdd4fbc69349af