Adds a FHIR bundle validation process task to the data-send process. Resources are validated against the GECCO 1.0.5 specification. Necessary FHIR metadata resources are downloaded, StructureDefinition (profile) snapshots generated and ValueSets expanded during startup of the BPE. Hence, the process plugin initialization code, needs to download FHIR packages and access a ontology server to expand ValueSets.
This PR also adds a stand-alone resource validator that can be used via the command line. Additional details see commit comment of 5da1517
closes #39