MAINT: review process document

[bsipocz]

Currently we have a notebook_review_process, but it is not included in the rendered pages.

@jkrick - please advise where would you like to see it in https://nasa-fornax.github.io/fornax-demo-notebooks/? Maybe a new, Contributor Documentation below the currently existing User Documentation?

[jkrick]

I am still waiting on input on the document from other team members, so for now, it should not be included anywhere. But, once it gets a review, I'd take your recommendation on where to put it.