Command line scripts in bin/ directory need to be moved to entry_points

[PennyHow]

For pypromice command line scripts (currently in the bin/ directory) to be cross-compatible for all platforms, they need to be moved to an entry_point, as specified here in the pypromice conda-forge build request: conda-forge/staged-recipes#22932

https://packaging.python.org/en/latest/guides/distributing-packages-using-setuptools/#entry-points
https://stackoverflow.com/questions/774824/explain-python-entry-points