Create documentation on setting up the Nano headless

[andrewg23]

Documentation on how to set up the Nano will be useful in helping others learn how to get started using the Nano. This documentation will include detailed instructions on the process required to get the Nano ready to use using only another computer. A headless Nano does not require a monitor, keyboard, or mouse.

[andrewg23]

I created a new branch, headlessDoc, to add any incomplete documentation that I don't think should be in the main branch yet. I specifically created this to experiment with uploading images to GitHub and adding them into markdown files in order to make progress on #2.

[andrewg23]

PR #10 merged the headlessDoc branch into main. The documentation on the headless setup is now up to date.
I think this issue can be closed after the documentation is reviewed by others and it is agreed that it is complete.