Microservice integration

[martypitt]

Create a workable demo of this project on Playground.

We don't support openAPI specs in the playground (yet), so taxi all the way.
Wire up stubs for querying

Write a README that has a bunch of different runnable queries, that the user can click-to-run.
Along the way, be sure to explain what's going on in the query (but don't be verbose)

• Filtering (client-side)
• Filtering (on an API)
• Nesting the data in different ways
• Returning the data as a CSV (not sure if this works in the playground, but lets find out)