TypeSpec integration with JSON Schema

Services that conform to industry standard data formats, e.g Health Insights and the FHIR standard, would benefit from TypeSpec support to directly import JSON Schema definitions.

An example of where this support would be really useful is the Health Insights service, which works with data that conforms to the FIHR industry standards, which have published JSON schemas, e.g.

[observation.schema.json.html](https://build.fhir.org/observation.schema.json.html)