Switch to tox

[prjemian]

Looks like an improvement. A switch to tox can be in a separate issue.

Originally posted by @prjemian in #276 (comment)

[prjemian]

In ophyd, tox is used in the documentation workflow:

      - name: Build Docs
        run: tox -e docs

and a linting step in the testing workflow:

      - name: Lint
        run: pip install --user .[dev] && tox -e pre-commit,mypy

note: Locally, I check workflows with nektos/act.