Phase 3: Add rest API helpers

[aleksa-krolls]

See parent issue #887 for details.

[martalovescoffee]

@hunterachieng could you please add an estimate to this issue?

[josephjclark]

Open question!

If we have the http. namespace to handle requests, is there any benefit in maintaining the rest get() and post() functions?

• Instead of get('patient/d3f7e1a8-0114-4de6-914b-41a11fc8a1a8'), you can just do http.get("/ws/rest/v1/patient/d3f7e1a8-0114-4de6-914b-41a11fc8a1a8")`. Not a big deal.
• You can use create and search to fetch and create resources. This should be cleaner and easier than using the rest API.

We could also consider getById(resource, ...id) or getResource which takes a resource and one or more ids. this is basically how get works today - I just want to use a different verb to decouple from the HTTP id. This is actually quite a common problem across the adaptors - we need a good synonym for get()

Having typed all this out, I think get(resource, id) is fine. No need for options. Throw if not found? use a throwOnError option?