Consolidate configuration definitions to pyproject.toml for modern python experience

[asears]

The pyproject.toml file can be used as the default configuration for tools such as pytest, flake8, ruff, mypy, sphinx, black, isort and build tooling.

https://docs.pytest.org/en/stable/reference/customize.html

https://setuptools.pypa.io/en/latest/userguide/pyproject_config.html

https://setuptools.pypa.io/en/latest/userguide/entry_point.html

https://github.com/cjolowicz/cookiecutter-hypermodern-python/

This would remove pytest.ini and perhaps setup.py and version info, and replace it with more modern pyproject.toml