Fix mme calc dose range

[bryantaustin13]

A medication using doseRange was erroring on ToQuantity:
org.opencds.cqf.cql.engine.exception.CqlException: Could not resolve call to operator 'ToQuantity(org.hl7.fhir.r4.model.Quantity)' in library 'MMECalculator'.
Adjusted MMECalculator.ToQuantity to handle this using quantity.system.value = 'http://terminology.hl7.org/CodeSystem/v3-orderableDrugForm'. This might be too specific and need adjustment. To test do
POST http://localhost:8080/cds-services/opioidcds-08-order-sign
and use the requests
https://github.com/cqframework/opioid-cds-r4/blob/Fix_MMECalc_doseRange/input/pagecontent/requests/OpioidCDSREC08OrderSign/request-example-rec-08-order-sign-mme-doseRange.json
AND
https://github.com/cqframework/opioid-cds-r4/blob/Fix_MMECalc_doseRange/input/pagecontent/requests/OpioidCDSREC08OrderSign/request-example-rec-08-order-sign-mme-greater-than-fifty.json
plus whatever other testing is needed. Both these should return cards.

[brynrhodes]

So this logic seems to be trying to account for the case when the FHIR.Quantity provided has a system of "orderable drug form", and appears to be collapsing the "unit" and "code" elements in that case. So a couple points:

1. It's never safe to use the "unit" element formally, that's not constrained to be a code of the given system. If a system is specified, the Quantity should have a code value from that system. If it doesn't that's invalid FHIR data and we should not be calculating with it
2. We can't just use the code from a system of "orderable-drug-form" as a UCUM quantity, we would need to convert from the orderable-drug-form code to a corresponding UCUM unit. Looking at the orderable-drug-form code system though, that doesn't seem computable: https://terminology.hl7.org/3.1.0/CodeSystem-v3-orderableDrugForm.html

So, where are we getting a quantity that has that system?