Reinitialise or test the radio IC periodically

[darksidelemm]

On Horus 62 the radio stopped transmitting partway throughout the flight, cause unknown. No residual carrier from no modulation, the radio just turned off somehow.

At the moment we only configure the radio once, when we run start_tx.sh. Instead, we should be moving this initialisation into the PacketTX class and regularly try and communicate with the radio, and reinitialise it if necessary.

[darksidelemm]

Experimenting with this in the rfm98w_packettx branch. Installation instructions here: https://github.com/projecthorus/wenet/wiki/Wenet-TX-Payload-Instructions-v2-(libcamera)