Migrate test and docs extras to PEP 735 dependency groups

[h-mayorquin]

This PR migrates the test and docs development dependencies to be conformant to PEP 735 by moving them from [project.optional-dependencies] to [dependency-groups]. The advantage is that dependency groups are not packed into the distribution for most users and are better handled by package managers like uv.

[alejoe91]

I think we need to update the .readthedocs.yaml too

[h-mayorquin]

I think we need to update the .readthedocs.yaml too

Done.

[h-mayorquin]

I also added dev with everything that is needed.

[chrishalcrow]

I'm getting issues with python >= 3.12 and matplotlib < 3.5:

      AttributeError: module 'configparser' has no attribute
      'SafeConfigParser'.

Tried taking the restriction off of matplotlib in docs locally and everything built ok - can we do that here and see if the CI runs ok?

[h-mayorquin]

I'm getting issues with python >= 3.12 and matplotlib < 3.5:

      AttributeError: module 'configparser' has no attribute
      'SafeConfigParser'.

Tried taking the restriction off of matplotlib in docs locally and everything built ok - can we do that here and see if the CI runs ok?

Yes, let's try.