vtkInformationDataObjectKey: move to CommonDataModel

It requires vtkDataObject which is in vtkCommonDataModel, but adding the
dependency link creates a circular dependency graph. Instead, move the
implementations of the convenience methods to the correct library and
export them from there.

Change-Id: I8bf68670aff5f703688cf9cbae83e683bd457f0f
Merge topic 'fix-dataobject-information-key-dep' into master

6b4ea15f vtkInformationDataObjectKey: move to CommonDataModel