Multiple linters

[jmccartin]

Seems like there are multiple Github workflow files which check the code for various formatting (flake8, pylint, and black). Since black is the most strict, why not just run that one? Consolidating would simplify contribution guidelines, save on build minutes, especially if using free actions and scope of tests increases in future.

There are also some conflicts in each of the settings files (.flake8, pyproject.toml) regarding line length and ignored exceptions. Moving completely to black will probably fix these, as it's generally without configuration.

[jmccartin]

Seems like flake8 is pyproject.toml ignorant - one of the few Python linters that remains that way for some reason. The imports in the code currently go against PEP8 recommendations, which flake8 will only pick up on with optional extras, like flake8-import-order.

I think most of the functionality there can be done with black and isort instead. The latter does better sorting of imports (with optional checks for CI tooling), so we can probably do away with flake8 all-together.