Figure out how RTD manages documentation versions

[npetersen2]

Start by reading this: https://docs.readthedocs.io/en/stable/versions.html

[npetersen2]

@elsevers and I will sit down and figure out how to get versions to appear on the RTD page.

An example of a project which does this nicely is: https://pymongo.readthedocs.io/

We should strive to replicate this type of capability, i.e., being able to look at published docs online from any released version.

[npetersen2]

Next steps:

1. Log into RTD and update latest to use eMach's develop branch
2. Then, release code like AMDC-Firmware (release branches, tags, etc), see https://docs.amdc.dev/firmware/development/index.html

[npetersen2]

This is completed by @elsevers