Add sphinx documentation and publish to ReadTheDocs

[astrochun]

Pretty simple feature.

• [x] Include a docs/source folder containing documentation.
• [x] Add sphinx-build GitHub actions
• [x] git_info update
  • [x] Static type hinting in git_info
  • [x] Docstrings update
• [x] Rename to redata-commons
• [ ] ~For simplicity, I recommend changing README.md to README.rst so that all documentation is using consistent format.~ (this is a separate issue that will be addressed after publishing)
• [x] Publish it as redata-commons.readthedocs.org