Migrate sktool's setup.cfg to pyproject.toml

[vanderhe]

[vanderhe]

@bhourahine Switched to Python >=3.10.

[samtsevich]

@vanderhe What do you think about installing the package via just pip install .[skprogs] which compiles all necessary binaries from the Fortran files inside the procedure? I guess, a good example of this is numpy.

[vanderhe]

@vanderhe What do you think about installing the package via just pip install .[skprogs] which compiles all necessary binaries from the Fortran files inside the procedure? I guess, a good example of this is numpy.

@samtsevich We decided to package most of our projects via conda-forge, instead of e.g. PyPI or on-the-fly compilation using the pip mechanism, so I don't think there are any ambitions to support another type of installation.