Make cuthbertlib an independent package

[Sahel13]

Makes cuthbertlib an independent package that we can publish to PyPI, while at the same time maintaining an easy way to install both packages in editable mode locally for dev.

[SamDuffield]

I think this is a good solution. I didn't immediately like the additional folder required for cuthbertlib but don't see a better solution.

I think it would be good for cuthbert and cuthbertlib to have the same version (like jax and jaxlib) this can be done by setting the version as dynamic in the pyproject.tomls and having the version specified in a separate file).

[SamDuffield]

@Sahel13 here if I do pip install -e . from root it will install the local cuthbertlib?

[Sahel13]

@Sahel13 here if I do pip install -e . from root it will install the local cuthbertlib?

I haven't tested pip, I'll try this now. But if we use uv sync --all-packages --extra tests --extra docs, it works.

[Sahel13]

pip ignores the settings for uv, so we need to run

pip install -e ./cuthbertlib
pip install -e .