[properties][cleanup] deprecate property GridView and replace by GridGeometry::GridView or Grid::LeafGridView

EnableGridGeometryCache

Reflect the change introduced by commit 83fe871a to the Dumux master.
Prevent deprecation warnings.

[course][exercises][naming] adapted towards the general naming conventions, unified naming of files and executables for the course

Make solution files and exercise files more equal

removed TypeTags endings and changed names of struct, if necessary

removed TypeTag ending and and added suffix NC for Stokes and OnePNC for Darcy

removed TypeTag ending

update readme

changed to
box.hh
cctpfa.hh
ccmpfa.hh