GHG fix quantity kind

[kschweikert]

ghg currently has a unique 'Amount' instance for every measurement that acts as both the quantity (QuantityValue) and the quantity kind. The quantity kind needs to be fixed.

https://lucid.app/lucidchart/720ca2ee-e1ae-45f2-8c64-4f4b3373f0ab/edit?invitationId=inv_dca258ac-01c8-4702-ac60-f6a4b4fe5c4d&page=A.gk9Th5EV-O#

I am still unclear what an instance of quantity kind should look like based on this diagram. is it unique per dataset/based on measurement type and contaminant?