Improve UX

[smalyala]

• Update docstrings to numpy style and method default values to match pachctl Convert/rewrite our docstrings to use NumPy-style doc strings (very low priority for release) #337
• Host docs on Read the Docs Move from pdoc to ReadTheDocs/sphinx (very low priority for release) #338
• Add wrappers to protobuf objects to make them more pythonic
• Address PFS: "all commits" should not be referenced as commitSet - (Parity with core Pachyderm 2.0) #316

[msteffen]

For the first item on your list, I broke it down into #337 and #338, so that we could add them separately to the python-pachyderm project. Let me know if that works for you

[smalyala]

Good with me