Draft: Add virtualized grid

This MR implements a virtualised version of the DUNE grid interface.

It takes dimension and world dimension as template parameters, and then can be constructed by passing another grid to the constructor. For instance:

Dune::VirtualizedGrid<2,2> ( yaspGrid );

Related MRs: !573 (closed), !656 (merged)

TODO

• Specify communicate following the idea sketched in https://gitlab.dune-project.org/-/snippets/71
• Improve performance of benchmark: https://gitlab.dune-project.org/simon.praetorius/benchmark-grids
• Clarify void communicate ( CommDataHandleIF< DataHandle, Data > &dataHandle, InterfaceType interface, CommunicationDirection direction ) const