Port spake2p tool to Python

[Damian-Nordic]

Problem

spake2p tool for generating Spake2+ verifier can be quite easily implemented in Python.
Python port would be more portable and easier to integrate in build systems.

Proposed Solution

Tennessee has almost complete implementation. We just need to add command line parsing.

[ihidchaos]

Agreed, this will make it easier to use spake2p and chip-cert on windows platforms.