Replace pydoc-markdown for Py Client API generation

[voetberg]

pydoc-markdown is not the best maintained project by their own admission, so trying to update it is tough. It should be replaced with something more widely used and actively maintained. Options include:

• MkDocstrings (or just straight mkdoc)
• Sphinx autodoc extension
• pdoc

[voetberg]

Some things to note here after looking into this briefly.

• pydoc-markdown was being used because we wanted to have generated markdown files then generated into html by docusaurus. This can hypothetically be done by mkdocstrings, but not by sphinx or pdoc.
• The existing pyclient documentation cannot support code blocks or any sort of rendering besides for the fields "arguments", returns", and "raises"
• We can use any of the proposed replacement methods to do something similar to the existing rest api documentation - create an html index that has a different website styling, and just link to it at the top of the page

There's also this fun little gist I found during research that goes over the scope of work to write an entire custom docs website without using any of these methods, built off docusaurus. For reference. https://gist.github.com/rb-determined-ai/afcbc11c5c81d9c8cc267e2796022ec5