Support querying historical fact data

This is a follow-in to PE-1745. We need to determine what sorts of queries we need to support against historical facts. If we want to support full fact queries, we'll have to have some way of time-constraining them against certain catalogs or something similar, and that could get quite complicated.

Alternately, it's possible that we only expose historical facts on a per-catalog basis, so we'd have a much more limited query API.

Or... we could decide that queries only reference historical facts when you're doing queries against reports, and the report data ties in to the fact data.

Probably a good idea to get some more input from UX (Joseph Wagner) about what all he has in mind for the UI so that we can make sure we meet those needs.