Complete order-sign and order-select CDS hook model and data generator implementations

[jenniferjiangkells]

order-sign and order-select require additional required fields of draftOrders and selections which have not been implemented yet.

draftOrders: A Bundle of FHIR request resources with a draft status, representing orders that aren't yet signed from the current ordering session.

selections: The FHIR id of the newly selected order(s). The selections field references FHIR resources in the draftOrders Bundle. For example, MedicationRequest/103.

Steps required to complete this task:

• Implement data generator methods for MedicationRequest, ProcedureRequest, ServiceRequest FHIR resources
• Implement data generator logic for order-sign and order-select workflows
• Implement validation logic for selections field in OrderSignHookContext Pydantic model
• Test this against Epic FHIR sandbox

[jenniferjiangkells]

@ganeshanrajan-sgt, please reply to this comment so I can assign the issue to you, let me know if you have any questions!

[ganeshanrajan-sgt]

@jenniferjiangkells please assign it to me. I do not have any questions at this point.

[ganeshanrajan-sgt]

Implementation plan ...

1. Review healthchain/models/hooks : orderselect.py & ordersign.py
2. Complete the Fields definition : selections & draftOrders
3. Implement validate_selections() method in both
4. Create a utility healthchain/utils/ordergenerator.py with generators for MedicationRequest, ProcedureRequest, ServiceRequest FHIR resources along with Bundle
5. Generate default data for draftOrders using the ordergenerator
6. Verify support CDS Hooks in Epic Hooks documentation for R4/STU
7. Test the compatible hooks in Epic Sandbox, using a end2end test py
8. Create a cookbook