Create CommonObjects in geometry

[ChasingNeutrons]

There are a variety of circumstances in which a certain geometry structure might be used by, e.g., a universe, a field, or even a tally.

The motivating example is a Cartesian lattice which we use in latUniverse and cartesianField. These two objects have quite a lot of duplication which could be overcome if they both instantiated a cartesianLattice object, endowed with distance calculations and cell identification.

I can imagine this might be useful for other geometry objects too, like unstructured meshes.