Webradio / A2DP sink using ESP32

ESP32-A2DP as submodule, because it wasn't published to platformio library registry.

PCM5102 as DAC, connection:

VIN -> 5V
GND -> GND
LCK -> ws_io_num (25)
DIN -> data_out_num (17)
BCK -> bck_io_num (26)
SCK -> GND