Sphinx docs

[chashton404]

Port to Sphinx with MyST

• I created a sphinx-docs folder that contains the docs for each of the four chapters of documentation (Operator Inference, Api, Tutorials, and Contributing) that we already have on the website. The data will need to be downloaded for the documentation to be built.
• The sphinx documentation can be built using the updated Makefile and tox.ini file using make sphinx_docs