Initalize package documentation

[namurphy]

Description

Added the framework for building documentation with Sphinx, with the markup syntax set to reStructuredText by default.

Documentation can now be built with nox -s docs in the top-level directory of the repository.

Motivation

If code isn't documented, it doesn't exist.

Details

After installing sphinx, I ran sphinx-quickstart and followed the prompts.

I also added the docs session to noxfile.py. The documentation can now be built by running nox -s docs in the top-level directory of the repository.

Future work

• Decide on a theme! Probably something from the diataxis model for docs?
• Finalize the name of the package 📛
• Creating a Read the Docs page for the documentation 📚
• Enable autodoc so that the documentation strings (docstrings) showing how to use each function get built into the documentation
• Enable awesome Sphinx extensions that are awesome 🌱

[namurphy]

My main motivation for adding this file is so that the directory shows up when docs are built in CI, and git only tracks files, not directories...