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.~~
and the space after "- ", but he didn't even touch this line, so let us try to focus on relevant changes and let us not blow up pull requests with that stuff.