Support Da Vinci CRD Payer implementation

[jdjkelly]

The Da Vinci CRD (Coverage Requirements Discovery) workflow deserves attention. The fact that it has a Payer involved is particularly interesting. The Payer side of the implementation involves creating CDS Services. Can we make a complete example?

• Can we conform to Da Vinci CRD http://hl7.org/fhir/us/davinci-crd/?
• Do we need to actually do anything or can we just make examples instead?
• Probably need to do something because the spec makes extensive use of the extensions keyword to load in extra stuff...
• Touchstone has conformance tests for this, so any PR should contain conformance results: conformance against this specifically: https://touchstone.aegis.net/touchstone/testsetup?name=CDSHSandbox-DaVinci-CDSH1-0-FR4-0-1-Test--All
• Formal spec is located here: http://hl7.org/fhir/us/davinci-crd/2019May/hooks.html

This issue can be closed either because it's determined that there's too much effort or if we have a working example that is publishable.

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Update: new goal

• Publish a working example at https://docs.sero.run/overview/examples/davinci-crd and in the examples directory

[mseckykoebel]

With #36 closed, I am now working on this from where I left off 21 days ago with adding extensions support to Sero. I imagine that an example in the examples might be enough to prove support for the DaVinci coverage requirements.

Therefore, shipping an end-to-end example will constitute closing this issue. I am going to try and work with one of the examples here as inspiration.