Optimistic Http Hydrate PoC

[WillBeebe]

• [x] it works in at least one case
• [x] tests pass

We could close: https://github.com/massdriver-cloud/artifact-definitions/pull/139

[WillBeebe]

[WillBeebe]

Making sure mass schema dereference still works with refs to local types.

[WillBeebe]

Closing, we won't support this in types