Boilerplate for FHIR API

[witash]

Describe the solution you'd like
Add boilerplate for a FHIR API in CHT Core
Using version 5.0.0 R5
See the FHIR standard for resource
The FHIR standard for a REST API
And the FHIR standard for security

Not everything in those standards will be possible or desirable for CHT core to implement.

A minimal implementation should include the following from the REST API

• Authentication with HTTP Basic Authentication
• read (for all types supported)
• search (for all types supported)
• capabilities

This requires

• pagination
• filters (as much as possible, not everything will be)
• metadata (as much as possible, not all attributes will be available)
• conformance layer including auto-generated capability statements

Notable items to EXCLUDE from the first version

• updating and creating resources
• authorization (for now assume a system user with access to everything)
• OAuth (basic authentication is fine for now)
• references between relationships

There are some node FHIR servers existing, and some functionality may overlap with cht-datasource.
Part of this issue will be investigating these solutions and see what can be used or re-used, and what should be implemented from scratch