Playground for the SA8x8 OpenRTX FW APRS TNC based on T-TWR Plus 2

https://github.com/OpenRTX/sa8x8-fw

Use PlatformIO to build and upload the firmware.

TODO:

• Basic structure for ESP32 and PIO
• BLE TNC
• Radio init FM@25kHz 144.800
• AX.25 to AFSK modulation
• TX Queue
• TX Beaconing
• RX Task with APRS decoding