v20230623 (r4)

Release r4 from 2023-06-23 which includes the following:

• Self generated trigger signal for connected MMIC radar on PA8
• SPI configuration of connected MMIC radar.
• Configurable SPI registers in spi_registers_db.h
• MCU ADC synchronization to self generated trigger
• FFT input is now $I - jQ$
• Ramp ID field to align with ramps generated by other radars in the network

v20221029 (r3)

Release r3 of firmware published on 2022-10-29