Adapt FHIR resource providers to reflect published implementation guide

[ohr]

There is a published implementation guide for MHD and PDQm:

• https://simplifier.net/IHEPatientDemographi?fhirVersion=STU3
• https://simplifier.net/IHEPDQmimplementatio?fhirVersion=STU3

and a 3rd party implementation guide for PIXm as well:

• https://simplifier.net/touchstonestu3/iti-pixmserver

Check compliance and adapt if necessary.

[ohr]

Specifically:

• extended operation for PIXm appears twice
• duplicated author parameters for DocumentManifest/Reference
• search parameter descriptions?