Create a python package for pulp-openapi-generator

[pedro-psb]

I was about to update the docs and started to think how I'd like to use that, so instead I wrote a docs to express how I would like to use that.
The idea is here as a draft docs: #102

Using a python package gives a very convenient workflow for generating bindings:

• very simple to install
• can be run from anywhere in the filesystem
• convenient for pinning versions

I couldn't think of any particular reason not to do it, but maybe there is?