Documentation update and dev tools suggestions

[eduardo-mw]

The following PR has 2 parts to it.

1. Additional documentation for public-facing methods and modules. I noticed there aren't many docstrings, so I just used the numpydoc format, which is good for in-depth documentation and is well supported by other tools like Sphinx.
2. Dev tools suggestions. There also didn't seem to be a preferred choice of linter, formatter, or dependency management tool. In my PR I propose ["pip-tools", "pylint", "black", "python-dotenv", "isort"] as these tools are fairly lightweight, integrate with existing workflow, play nice with each other, and have widespread support. I generated an example of what pip tools can offer with dev-requirements.txt.