Move tests to root, add pytest.ini_options, and use tox-uv

[TimMonko]

References and relevant issues

Closes #77

Description

1. moves tests to root and renames to tests (the latter of which, even if we keep in src, should be done according to PY005)
2. adds pytest.init_options (PP301-PP309)
3. replaces tox with tox-uv in dependencies to speed up tox runs

[willingc]

This looks good @TimMonko. I've made one small suggestion to assist the user.

[jni]

@TimMonko @willingc before merging this, could you please check and address the discussion on #77?

[willingc]

See #77 (comment) @jni

[TimMonko]

@jni can you follow-up on this just so we can make a decision for merge ❤️

[jni]

@TimMonko can you please double check that the pyproject.toml/manifest/whatever settings are correct here so that the tests directory is shipped in the sdist? If that's true then please go ahead and merge, according to the discussion in #77. Thank you!!! 🙏

[TimMonko]

Will check. I'm going to think about the comments more and try to find a simple hybrid to address as many situations as we can. I want to prioritize simplicity, but will make sure we get tests in sdist

[DragaDoncila]

Pulled this down and built a plugin and confirmed the tests are present in the sdist under the src/ directory. Going to merge now. Thanks @TimMonko!