Prune legacy code

[ThirteenFish]

-150k loc. Moving from OreSat0 to OreSat0.5 saw significant hardware changes that until this point hadn't been reflected in this repo. This commit removes support for the no longer used hardware, including old boards, drivers for no longer used devices, and STM32F4/L4 microcontrollers entirely. Of note:

• The archive is gone. Its contents, like the rest of the removals here can be accessed in git history.
• The C3 is now Linux based. Removing the old project means we can drop our custom ChibiOS patches, and also external dependencies on littlefs and OpenCCSDS.
• I tried to keep modified files to a minimum but do note sensors.h, can_hw.h, and the app_adcs Makefile.

[ThirteenFish]

We also could keep and fix sensors.[c/h]. I think it is still relevant to F0?

I've added it back in, but it'll need some work to get it functional again. The way it's currently implemented it steps on the toes of anyone trying to use the ADC, currently ADCS and the diode card.

[glennl]

For RF hardware things I occasionally use for testing with an F4 Nucleo, there are three (3) branches I go to. This stuff could possibly be moved somewhere that makes better sense, particularly since the code was initially created before there was any real working C3, but for some reason became part of oresat-firmware repo.

The names of the branches under oresat-firmware are:

• c3_synth
• c3_rf
• c3_L_test