emsig/empymod: libdlf and scooby

The digital linear filters are outsourced to libdlf, reducing the lines of code of empymod by over 50%. In addition to the new requirement libdlf, scooby is added as a requirement. Most user questions can be adressed much better if they provide the output of empymod.Report() - however, most users do not have scooby installed. Having it as a requirement will make support smoother. Both new requirements are very lightweight modules, having at most numpy as a dependency.

• Filters:

  • The digital linear filters are outsourced to libdlf (https://github.com/emsig/libdlf). Note: How to access filters changed! The old way still works, with a deprecation note stating how to change your code. The old way will be removed in v3.0.

• Examples:

  • @efinden expanded the "Cole-Cole IP" example.

• Maintenance:

  • Bumped the minimum requirements to:

    • Python 3.9
    • SciPy 1.9
    • Numba 0.53
    • libdlf (NEW requirement)
    • scooby (NEW requirement)

  • Testing: added Python 3.12, dropped Python 3.8.

  • Fix remaining outdated python setup.py commands.

  • Many small things to keep the package updated.