[WIP] ElasticSearch implementation

* [x] Create index mapping on model creation
* [x] Index on record creation
* [x] Search view, proxy on E/S
* [x] Search with request body
* [x] Search with URL parameters
* [x] Reindex on record update
* [x] Index individual records on model records PUT
* [x] Test model definition update
* [x] Test model definition mapping (shapes, etc.)
* [x] Test model record mapping (object, etc.)
* [x] Test spatial query
* [x] Return specific response code when *elasticsearch* not available/reachable