Icebox: For storing and serving OpenQuake results

"Icebox" is a component of the oq-platform which is responsible for storing and serving OpenQuake Engine calculation results. Icebox uses the oq-engine-server API (see https://blueprints.launchpad.net/oq-engine/+spec/oq-engine-server) to import calculation results and place them in permanent storage. (The OQ Engine database is considered temporary storage, thus the necessity for this step.)

REST API:
- /artifacts # summarized list of artifacts for the current authenticated user
- /artifact/:artifact_id # get the artifact (probably just as a geojson blob)
- /artifacts/import # parameters: platform owner user, (oq-engine-server) url to import results from; this implies that the icebox has some knowledge of the oq-engine-server API

DB:

For the first iteration of the database, we'll probably only need one table.

--artifact--
  * id (int)
  * artifact_type (string, 'hazard_curve', 'hazard_map', etc.)
  * name (string)
  * artifact_data (blob)
  * content_type (string, indicates the `artifact_data` content type--geojson, xml, etc.)
  * user_id (FK to oq-platform's Django user table)

UI:

No UI components specific to icebox are required at this time. The `explore` Platform component will use icebox's REST API and the `calculate` Platform component (not yet built) will use oq-engine-server's REST API. That's all we've thought of for now.