Testing and building

[christopherpickering]

Summary

This pr adds a few things to make building/testing better:

• added coverage
• added github lint workflow (uses mypy, black, ruff. more ruff codes should be enabled/fixed in the future.. trying to keep the pr small)
• change packager to poetry - much easier to releae and also manage the dev deps for all the backends
• added tox to run the tests
• added github test workflow
• added basic pre-commit file

After merging this we can rebase several of the other pr's and merge them with a few minor tweaks.

Using this:

Installing for dev:
poetry install

Running tests:
poetry run tox

Running for formatting & linting
poetry run tox -e isort,black,lint

[christopherpickering]

The failed tests are valid failures in the current code and either have or should have other pr's to fix them.

[christopherpickering]

moved to #170