This refactors out a bunch of code to make better use of the
SYSINIT mechanism...

Completes the PKI side of things for doing mutual authentication...

Uses a python script to generate the USB descriptors, and basic
interface code for the STM USB HAL Layer..  This gets ride of a lot
of the glue code that was previously written, allowing the glue code
to be easily changed/update...

break out the memory debug function into it's own file...

Minor fixes to the rs485 framing code...  Finally found the bug where
aborting a receive would corrupt the RX state for some reason...

Add back RNG seeding, and make it generic...

This follows the same protocol as the lora code, so the same
server should just work.

This gets USB CDC printing working..