properly automate and organize gh-pages build and deploy

[d-callan]

right now the gh-pages branch is a true branch of the repo, w all the files etc, where i manually run npm run build-docs and push the updated index.html file. id rather that branch only have the index.html probably, and have a github actions workflow to produce the new version on commit to master or something. no matter what we decide to do for user-facing docs, it seems a good thing to host the most updated/ dev version on gh-pages.