Lums/sphinx

[lums658]

Added initial support scaffolding for sphinx-base documentation.

• Created sphinx subdirectory under doc
• Will need to create CI workflow to build and push to gh-pages and/or readthedocs.io
• There are some particular requirements we will need to set up to make things work properly in the CI workflow. I've put them in doc/sphinx/requirements.txt, and I think they are complete, but there may need to be some experimentation. At some point I was using a custom-compiled doxygen -- that may or may not be completely necessary to use, but if it is, we'll probably want to pre-build it and use custom docker image for CI (if that is possible)
• Probably don't really need "exhale" as part of sphinx -- should set up to use doxygen directly from breathe
• Will need to add documentation to code
• Will need to create narrative in .rst files -- perhaps autogenerate from latex with pandoc?

Moved latex sources to a latex subdirectory under doc

[neoblizz]

Integrating this into Actions.