introduced proporties and propertydefaults for the coupled stokes-darcy
models, that the model does not have to use runtime parameters.
properties from the test problem headers have been moved to the model
properties.

reviewed by gruenich



git-svn-id: svn://svn.iws.uni-stuttgart.de/DUMUX/dumux/trunk@14045 2fb0f335-1f38-0410-981e-8018bf24f1b0