Turn the ATBD repo into a JupyterBook hosted on GitHub Pages

[yunjunz]

This repository (https://github.com/CIMR-Algos/TerrestrialSnowArea_ATBD) shows it's possible to combine a bunch of markdown files and Jupyter notebook files together into a Jupyter book (https://cimr-algos.github.io/SeaIceThickness_ATBD/intro.html), an HTML website hosted in GitHub Pages and compiled from the repo automatically. It will be really cool if we could do the same here.