Add moisture sensor connector. Add antenna connector. Swap MOSI/MISO to get the right way around. Add missing DIO1 <-> D3. Move around IN1, IN2, nSLEEP_HB to connect to the used DIOs on Arduino.

Add datasheets and schematics.

Add schematic derived from photos.

Add footprint for MP6550 and map symbols to footprints, using connectors for battery, etc.

Initial import