Asynchronous Cached Entities

Hooks to allow for platforms to intercept and provide caches for input tree references.

X-Requested: CommCare, CommCare-ODK

Relies-on: inline_entity_tiles
Yeah, order is meaningful. The ordering can make a big difference WRT performance. If the first filter is indexed, for instance, and cuts the scope from 100% - > 10% of the total cases, and the second filter isn't, the second filter only runs over the 10% of remaining cases, which is pretty huge.