Add Python module version attributes

[yrasool]

Fixes #17.

Adds __version_info__ and __version__ to the Python module so callers can read the package version at runtime.

Adds a small test for the version tuple, string, and string derivation.

Validation:

• git diff --cached --check
• py -3.10 -m py_compile python\mcnptools\__init__.py python\mcnptools_tests\__init__.py python\mcnptools_tests\versiontests.py