coso/pfas ContaminantMeasurement subclasses

[kschweikert]

GHG, EGAD and SDWIS triplification do not align on how ContaminantMeasurement subclasses identified.

Per latest discussion there should be 4 subclasses:

• coso:ContaminantVolumeMeasurement
• coso:ContaminantConcentrationMeasurement
• coso:SingleContaminantMeasurement
• coso:AggregateContaminantMeasurement

Each instance would belong to two of these subclasses.
Still need to clarify how the middle pfas ontology layer works.

• sdwis currently uses pfas:PFAS-ConcentrationMeasurement (parent only coso:ContaminantMeasurement)
• ghg uses pfas:PFAS-VolumeMeasurement subclassof coso:ContaminantVolumeMeasurement and coso:AggregateContaminantMeasurement (no pfas layer)
• egad uses pfas:AggregatePFASConcentrationMeasurement subclassof coso:AggregateContaminantMeasurement and pfas:SinglePFASConcentrationMeasurement subclass of coso:SingleContaminantMeasurement

all 3 of these need some changes to match the intended ontology for coso and pfas

[kschweikert]

egad has been aligned to latest coso classes.
Other datasets still need updates.