WIP: Support vtk output of multidomain grid views

What does this MR do?

Allows the vtkSolutionVTKWriter to write solutions on a subdomain of the grid view used for the grid function space. The main trick here is to explicitly store the grid view on the common data, together with a transformation from the subdomain to main domain.

Is there something that needs to be double checked?

• That the merge request core/dune-common!696 (merged) is already accepted
• How could I test this without having to add the dune-multidomaingrid dependency.

Can this MR be accepted?

• Implemented
• MR of Std::identity in dune-common is accepted
• Added test
• Pipeline passing
• Added entry to CHANGELOG.md

Related issues