Ned Coltman authored 2 years ago and Timo Koch committed 2 years ago

* Update the generators for the new spatialparams classes
* use the new problem and spatialparams classes

This reverts merge request !3055

The old one wasn't wrong but it seems to make more sense and easier to read
if the gridvariables are initialized before passing them to the assembler.

This allows to disable the Dumux Python bindings independent of the Dune
Python bindings.