Rolling back code about alloy

[GarrettBurroughs]

Also, fallback code that can be toggled

thanks to @jackhymowitz for this idea

[rafibaum]

I had an idea for a "dumb" way of doing this in FRC. I believe the code deployment process is basically a glorified SFTP copy of a compiled jar file to a specific folder on the RIO which gets run automatically on boot. You could have the code swap around the jar files on an error before killing its own process to have the RIO re-run the jar file (now the new hopefully error-free jar).

[rafibaum]

Doing this in FTC is a bit more challenging as there's no "dumb" way of doing it. You could package each revision of the code as a separate jar which gets loaded on demand by a version-switching stub which talks directly to the Qualcomm libraries and swaps out the jars appropriately (although to the user it would just look like you're switching teleop/auto modes).