Describes a request to the FHIR backend.
compartment can be of the form 'Patient/1235234' and is
an optional part of the request. entity is the entity being
queried and parameters optionally contains a list of
search parameters.
The FhirClient will assemble the request into the format
of fhirBaseUrl/compartment/entity?queryParameters.
It can optionally be used together with validators that will
change part of the request parameters during validation to
ensure RBAC restrictions.
