Improving onboarding and enabling contributions about graphblas-algorithms

[z3y50n]

These are all good points for a nicer, smoother onboarding process and making usage of graphblas much easier.

Personally, I feel we need to prioritize having a good reference documentation. This will at least give everyone the basic usage of graphblas' functions.

Besides that, a small tutorial like that of NetworkX could be helpful for a hands on example and exposure to graphblas.

[eriknw]

I agree with those priorities @z3y50n, thanks for the input.

Check out the documentation that @jim22k just created:
https://python-graphblas.readthedocs.io/en/latest/

I expect documentation will be an ongoing effort, so feedback is most welcome.