Support for querying a FHIR server

[serwarde]

Is your feature request related to a problem? Please describe.
INCEpTION projects contains documents that may have some additional metadata on an external server. Ideally, you'd be able to query this external server for this metadata, and then use it for generated additional plots.

Describe the solution you'd like
In this particular case, we need a connection with a FHIR server to check the type of the documents in the project, and then use the returned types to aggregate documents, and generated specific plots for them.

Describe alternatives you've considered
Alternatively, you can ask the INCEpTION project manager to create separate INCEpTION projects for each document type. This, however, is more logistical work for them, and doesn't insure consistent results.