Remove some obsolete files

[paulmelnikow]

• Where possible, migrate config from setup.cfg to pyproject.toml

[jbeard4]

What is the difference between pyproject.toml and setup.cfg? When should we now use one versus the other?

[paulmelnikow]

What is the difference between pyproject.toml and setup.cfg? When should we now use one versus the other?

pyproject.toml is the new package.json-like standard for Python: https://www.python.org/dev/peps/pep-0621/

flake8 doesn't support it:

• pyproject.toml (PEP 518) support PyCQA/flake8#234
• Migrate flake8 config to pyproject.toml johnthagen/python-blueprint#29

So we're using setup.cfg, which is a legacy setuptools-related format.