Change to Pyproject.toml installation and uv, remove python 3.8 support, add python 3.13 and 3.14 support

[gnzng]

Commits from this PR were recently discussed in #56:

be28903:

• change the CI tests to remove the dependency on requirements.txt and removes outdated setup.py
• pypi build now also uses uv (much faster)
• switch to a pyproject.toml

728cf9d:

• Update the install docs and readme to match installation

[gnzng]

@allevitan it looks like we are losing python 3.8 with the latest pytorch version:

Run uv run pytest
error: Distribution `torch==2.5.1 @ registry+[https://pypi.org/simple`](https://pypi.org/simple%60) can't be installed because it doesn't have a source distribution or wheel for the current platform

hint: You're using CPython 3.8 (`cp38`), but `torch` (v2.5.1) only has wheels with the following Python implementation tags: `cp39`, `cp310`, `cp311`, `cp312`, `cp313`
Error: Process completed with exit code 2.

[allevitan]

@gnzng What do you prefer to do? Drop support for python 3.8 or test with an earlier version of pytorch?

[gnzng]

@allevitan I would probably recommend discontinuing support for Python 3.8, as it reached end of life and no longer receives security updates.

[allevitan]

Agreed

[allevitan]

I tested installation from source with the new pyproject.toml on my system and went through the files. I just have a few small comments to address before we merge.

[allevitan]

Looks good