Dosing, quantity, dispensing and duration units concepts should be defined via global properties

TODOS:

• Add the following global properties; drugorder.dosingUnits and drugorder.getDispensingUnits where their values are uuids for concepts which must be a Sets, the idea is that the set members constitute the list of concepts to be returned by the following methods that need to be added too, (see how OrderService.getDrugRoutes() was implemented). It would be nice if these method cache these lists of concepts and update them via the GlobalPropertyListener mechanism

  List<Concept> getDrugDosingUnits() 
  List<Concept> getDispensingUnits();
  

• Remove the changeset that adds Units Of Measurement concept class
• Remove org.openmrs.ConceptClass.UNIT_OF_MEASUREMENT_UUID
• Update DrugOrderValidator to validate the concept for doseUnits and quantityUnits to ensure it is among those specified by the global property.
• Update MigrateDrugOrderUnitsToCodedDoseUnitsChangeset to ensure that mapped concepts match those listed for their respective global properties

Extra Credit:

• Update the 1.10 upgrade helper module to not use the units of measure concept class and probably use these global properties too.
• Update order entry UI module to use the concepts returned by these methods to populate the dosing Units and dispensing quantity fields instead of concept classes.