Create hardware compatibility guide

[jweisz]

Create a hardware compatibility guide that explains what you can do with TJBot depending on which RPi you use to build it. E.g. if you have an RPi 3, you can do X, Y, and Z. If you have an RPi 4, you can do X, Y, Z, A, and B. If you have an RPi Zero 2, you can do X and Y.

[jweisz]

Low priority for now until we actually build a TJBot with a Pi Zero.