Tons of varying changes

[56kyle]

There is way too much to go over here, but here are some broad ideas and concepts that either occur here or that are being explored:

• Using pytest to test the cookiecutter template
• Automating the use of retrocookie with linting to allow for quicker turnaround on pre-commit adherance
• Integration testing with a github repo at both https://github.com/56kyle/robust-python-demo and https://github.com/56kyle/robust-maturin-demo
• General fixes
• Using nox tags for sessions that need to be grouped
• Trying to reduce number of nox sessions, or at least to make them orthogonal to eachother to some degree