[FEATURE] Add firmware instructions to documentation

[darigovresearch]

Is your feature request related to a problem? Please describe.
There currently is no instructions/documentation on the firmware as in the folder readme

Describe the solution you'd like
Take the content from here and put it in a page of the documentation

Describe alternatives you've considered
Leave it in the readme but having it all in one place would be helpful

Additional context
N/A

[leonhma]

made #54 to reflect latest changes

[darigovresearch]

Thanks @leonhma, hopefully the discussion in #48 will help move this forwards

[leonhma]

I made #54 by just converting firmware.md and adding it online. (Still has to be merged I think). As #55 noticed, some details don't match up. I think we should merge it first and then figure out some of the wrong details.