FhirValueSetEnumInterface and system OIDs

[qligier]

When value sets are generated, the system may be an OID. In that case, it is not URN-encoded. I removed the URN-encoding in eMed value sets in c029d01 (RouteOfAdministrationEdqm was the last one), the EPR value sets were never affected by the URN-encoding.

The issue is that the implementation of Coding getCoding() and boolean isEqualTo(Coding) (from FhirValueSetEnumInterface) do not add or remove the URN-encoding, as required by the FHIR specification.

[qligier]

Also, in getCodeableConcept(), we set the wrong value in the text. Currently, we use the code system name instead of the code display name.
It's a different issue for the generator, but will be solved in the same PR for Husky.