Support source control of production utilities with decomposition

If production decomposition is enabled, any attributes of the production class other than the production definition are not source controlled. For example: custom methods, properties, parameters, or the class's superclass. The current best practice is to put any utility methods in a separate class.
We should get to a point where all production class attributes are source controlled. Potentially with a separate PTD document or a custom document type for "production class without definition".