GitHub Actions pytest workflow now uses uv instead of nox

[tleonhardt]

GitHub Actions pytest build workflow now uses uv instead of nox.

Also:

• Removed noxfile.py
• Remove dev/test dependency on nox

NOTE: This reduced the average build time from a little over 3 minutes to a little over 2 minutes for running all of the tests. There is still a lot of room for optimizing the build time including:

• Install Python from uv instead of the GitHubActions
  • This failed on LInux due to lack of readline. We could fix that by also installing gnureadline on that platform for test runs.
• Use uv caching to store uv's cache across workflow runs