Convert `FhirResource` from class-based to functional component

[jocelynn1uphealth]

Background:

Migrating from class-based to functional components improves the bundle size and performance of the repo

Expected Behavior:

• no user-facing changes should result from this change
• components work as expected
• the FhirResource class is gone and has been replaced with a functional component of the same name
• the FhirResource component has been moved into its own file
• stories + supporting documentation have been updated

[patrick-1upHealth]

Addressed this and #399 in https://github.com/1uphealth/fhir-react/pull/404