role-based auth, prompt chat endpoint, unit tests

[maxnorth]

Ton of stuff in here, should break this up into multiple commits but we're pressed for time.

Highlights:

• Implementation of role-based authorization for http functions
• Infrastructure for generically creating chat prompts via azure storage queue & azure function queue trigger, plus an endpoint for prompting all people within a country to enter a report (this needs to be modified to only query on members of a particular admin stack, but this data still needs to be modeled).
• Unit test infrastructure and initial pass of tests for chat prompt and chat registration, including happy path, bad request, and various authorization scenarios.
• Some general renaming/moving around of files for more sensible patterns of project structure.

[maxnorth]

Closing, these changes were collapsed into #131