Add org API client

[ChrisPenner]

Overview

Ugh, servant-client reaaaaally doesn't work so well with nested APIs like this. I got something half-decent, but manually re-wrapping all the endpoints is pretty annoying.

• First merge cp/add-org-client into unison

Implementation notes

• Adds a ton of missing FromJSON and ToJSON instances to support the Client side of the equation

Test coverage

• Servant should do the bulk of the work ensuring that these behave as intended :)

Loose ends

I had to manually split off just the org api as its own thing; getting the entire API working as a valid client is largely untenable, there are responses which can't/shouldn't be deserialized back into their source (e.g. some namespace diff types lose information as part of serialization, maybe we shouldn't do that).