Merging my changes for Dataset Documentation onto documentation staging. Once this PR gets approved, a github action will be triggered that also updates the gh-pages branch of coderdata, which will update the actual coderdata docs webiste: https://pnnl-compbio.github.io/coderdata/index.html .

Marissa made some wonderful documentation about how to use sphynx/update the docs here: https://github.com/PNNL-CompBio/coderdata/tree/documentation-staging/docs . There's information there as to how to preview the updated pages.

Closes #337