Packaging

This is an issue to discuss how we can package moringa thus allowing pip install moringa.
It also implies to organize the code in one or several modules, so we can also discuss about how we need to separate things (code logic, and hypothetical optional dependencies for compatibility with other python tools).

Since PEP621 it's quite simple, with a single pyproject.toml file and setuptools.
You can see how how did this with pyotb here. It's really nice for automatic creation of executable scripts that are installed in PATH.