Use GitHub Pages

[katrinleinweber]

I think this does it. make html noew produces a page looking pretty much exactly http://www.pgweb.uni-hannover.de/, when I open the offline /docs/index.html in the browser and when committed to https://katrinleinweber.github.io/radproc/.

[jkreklow]

Thanks for your efforts, that looks like a really good start! Unfortunately, the images and the notebooks (tutorials) are not included, which may be due to a sphinx extension lacking in your system configs. But as I now know what the directory structure needs to look like in order to make gh-pages publish the docs I can try to fix these errors locally and commit the prepared docs to GitHub.