host notebooks as Documenter documentations on GitHub Pages

[aviatesk]

Renders the handbook as Documenter.jl documentation, and host them on GitHub Pages. In my opinion, the notebooks would look nicer on Documenter.jl documentation rather than on GitHub nbviewer.

Once we setup SSH deploy key for this repository, the pages will be hosted on GitHub Pages. I already hosted documentations on my clone, and it looks like this: https://aviatesk.github.io/diff-zoo/dev/