Implement a CI script so that we can see live docs for each PR

[daquinteroflex]

Readthedocs already has a similar feature..
However, we don't want to use readthedocs as we want to manage our own build hardware using github actions eventually. So, how can we do this for a given docs PR into autoflex? Ideally it can be done in a way we can resue for other projects.

Note that this might involve a better way for hosted version management. Ideally the action runs automatically and this just creates a directory for each docs PR. It'd be nice if the directory got deleted after the PR gets merged.

Maybe a small architecture demo is good enough to iterate on.