Support UOMs across AF databases within an organization

UOM conversions done on one AF Instance cannot be referenced by another AF Instance, even for the base/built-in UOMs. A customer uses an AF pattern where they have a golden (reference) AF structure that is referenced by other AF structures to help insulate us from changes in PI (ie. swap out a sensor). Because applications are complex, they are sometimes deployed in separate AF instances. The UOMs can be standardized across instances, but conversions are not always supported.