Add "Stale Query CSV" capabilities

With the new Stored Queries functionality, complex SQL queries can be run against the Datastore and stored as snapshots.

However, it seems that there is no mechanism to ensure the snapshot is up-to-date. As I understand it, automatic refresh was not implemented as a conscious design decision so as not to trigger cascading updates that will negatively impact performance.

It would be nice if:
* there is a "Stale Query CSV" indicator in the UI that will prompt data publishers to refresh a query
* have the ability in the UI to click through the parent resources referred to in the SQL
* there is an API for helping manage the Query CSVs - to find out stale CSVs, to find out the query dependencies, to trigger a query CSV refresh.

cc @wardi

Start with the Stored Queries functionality in the Datastore and the SQL query dependencies described in the issue. Define the scope for stale-query indicators, parent-resource navigation, and an API for finding stale CSVs, inspecting dependencies, and triggering refreshes; this is done when those behaviors are specified and implemented across the UI and API.

Written by the indexing model from the issue text.