No connections from FPGA to bluetooth audio

[gardners]

In the redesign, we seem to have left out the means to pipe audio to/from a bluetooth module. The ESP32 can act as BT module, but we don't have the 4 extra PCM lines routed to it.

Simplest approach is probably to route 6 FPGA pins +3.3V and GND to an 8-pin header in the corner of the PCB near the TE0725 at the opposite end to the HDMI connector.