Merge DomainInformation and SubGrid

Fixes issue #416 

 - move Selection to PMacc
 - merge DomainInformation into SubGrid
 - remove SimulationBox from SubGrid

I tested this with a 128/512/128 4 GPUs LW moving window simulation - images looked good.
~~Note that there might be some documentation still missing.~~
the `DataSpace` should be templated with `simDim`, too - right?