Support for VRDR Messaging Client Interaction

[pkmitre]

In addition to functionality for generating and consuming VRDR FHIR Messages as described in #4 the VRDR Java library should also provide features to simplify interacting with the NCHS and STEVE FHIR APIs such as retrieving OAuth tokens, submitting messages to the API, receiving responses from the API, and bulk messaging. This support should have functional parity with the VRDR Client library at https://github.com/nightingaleproject/vrdr-dotnet/tree/master/VRDR.Client

[MikeRileyGTRI]

Going to add a pitfall here; you need to be careful in the java environment about which type of HttpClient you use. If you use the hapi fhir RestClient, there's an assumption of apacheHTTP (Although this can be configured and changed). Not every Java envrionment will support it right out of the box (99 percent will though). Just need to be careful about the library dependencies and make sure partners are ok with them.