Implement support for FHIR security labels

[fredhersch]

FHIR Security Labels are a way to classify different resources. Based on these tags, certain resources can be filtered out depending on the access provided to the requester.

For example; a CHW that should not have access to any resources that could indicate that Patient A has a specific condition (for example, HIV).

Implementing this "information classification" system has multiple parts:

• Evaluate existing Info Gateway AccessCheckers to write queries that utilze security labels
• Determine whether new features of an API should be added for the classification system
• Estimate and implement this