Create mappings between Kids First and FHIR Phenopackets

[liberaliscomputing]

Create mappings between KF and FHIR Phenopackets models, using this spreadsheet. This is part of https://github.com/d3b-center/clinical-data-flow/issues/15. The followings are an order of actions:

• [x] @liberaliscomputing will populate Column A (KF Concept Attribute) against the intermediate PCGC data persisted in the KF Warehouse DB. The KF data service REST documentation is also available here;
• [x] @liberaliscomputing and @ShahimEssaid will 1) split Participant, Observation, and Specimen resources and 2) map KF concept attributes and FHIR model attributes, using Phenopackets; and

[znatty22]

Closing this since its complete and we are moving on to developing a Kids First FHIR model from scratch.