Add view constraints for derived partition fields.

Views currently only support constraints expressed in terms of the entity's data fields and not on derived partition values. This is limiting because it is more difficult to ensure views align with partitions. This is currently blocking the Oozie coordinator work.

The argument against allowing constraints on the partition fields is that the partition functions are no longer internal details, but are exposed. But, this is the case anyway because partitions are already exposed through Hive.