PDS FHIR API supports capabilities interaction
FHIR R4 includes the capabilities interaction: "Applications SHALL return a resource that describes the functionality of the server end-point." [https://www.hl7.org/fhir/http.html#capabilities]
PDS FHIR API returns OperationOutcome "FAILURE_TO_PROCESS_MESSAGE" when using this interaction.
Please implement this so that:
1. PDS FHIR API respects the FHIR R4 standard
2. engineers familiar with FHIR can more easily understand the capabilities provided
3. software can use the capabilities interaction to interact with different FHIR MPIs