Typing and docstring support for better IDE experience

[Zensonaton]

Is your feature request related to a problem? Please describe.
When using RethinkDB driver, there aren't any type annotations or docs. All of the methods looks like this:

Describe the solution you'd like
A type annotations and docstrings for methods and classes.

[lsabi]

Hi @Zensonaton

We're working on a revamp of the driver. It is not currently finished yet, but yes, we're working on docstrings too with the port from python 2 to 3. You can follow the progress here

#277