Apart from squashing begin, end, entityOrientation and entityBasis
parameters into TraverserKernelData, this does not improve performance
of the LinearSystemAssembler, ExplicitUpdater etc., but in tnl-mhfem it
allows us to pass MeshDependentData, which is already available as a
SharedPointer, directly to the grid traverser without duplicating the
transfer to GPU.

I think this is much better because even operators inherit from Domain
and operator.getDimensions() is very confusing.