335 rm mkdocs add sphinx

[hausman-gdit]

Closes #335

mkdocs to Sphinx

• new dependencies (the new style isn't necessary just for pizzazz)
  • Sphinx documentation
  • myst-parser md parsing
  • pydata-sphinx-theme style
• change shapiromatron/ links to USEPA/ & change repo name
• Stole as much styling as possible from WNTR. I think the example output PDF goes through another post-processing step that adds in the cover/back pages.
  WNTR's latex output seems to be trimmed down (https://github.com/USEPA/WNTR/blob/f07682bc0e3f19425808d4fae4ad1ad0039c21c6/documentation/conf.py#L363)

Pandoc is required to convert from html -> docx. From docx, we can convert to PDF.