Rename SubdomainIDGenerator

[GiudGiud]

Reason

Bad name. It does not tell you what it does. Maybe SubdomainPerMeshGenerator ? All the SubdomainXXXGenerator do this re-districiting operation. They should all be ReAssignSubdomainXXXGenerator. But I can live with the lack of verb prefix.

Design

New name, fix deprecation

Impact

More usable moose, less time spent looking at a list of object and clicking around to know what they do