Add non-Darcy flow upscaling example

The following discussion from !2420 (closed) should be addressed:

• @timok started a discussion: (+2 comments)

  I would be awesome to have a test that computes permeability in one direction for a network e.g. extracted from the Berea sandstone sample for different pressure gradients. Then we could do at least a qualitative comparison with Muljadi et al. https://doi.org/10.1016/j.advwatres.2015.05.019 (essentially reproduce one of the plots of El-Zehairy et al. https://doi.org/10.1016/j.advwatres.2019.103378)