BluetoothA2DPSinkQueued and more Callbacks
- Provide BluetoothA2DPSinkQueued class which uses an additional Queue between A2DP and I2S
- Redesign reconnect logic to prevent an automatic reconnect after a disconnect has been requested via the API or from the remote system
- increased volume for bt_music_receiver_32bit_ext example
- Added support for a post I2S init callback (thanks to adam-puleo)