Refs #10281. Changed CenteringGroupCreationHelper again.
Refs #10281. Decided to change CenteringGroup helper once more

Having a singleton is better than having a static member variable which depends on initialization order. And it's better than to fill the symbol/type map every time a centering group is constructed.
Refs #10281. Removing output generating unit tests
Merge branch 'feature/10281_space_group_and_factory' into develop