Add end-to-end tutorial how to speedup Python using Fortran

[certik]

First requested here: https://twitter.com/MattAlhonte/status/1579726103123722240

Is there a good end-to-end "find some Python data code is running slow, identify bottleneck, drop down into FORTRAN and make a little optimization, and then be able to call it from Python" tutorial out there?

[certik]

As a subset, we also need a tutorial how to wrap Fortran into Python, we can port it from our old page:

• https://www.fortran90.org/src/best-practices.html#interfacing-with-python

[awvwgk]

See #105