preloading high-value entity metadata

[Cantor, Scott]

> I think you'll get the idea fairly quickly without having to wade through all the
> details.

Our decision was that if you want to pre-fetch, you can do that yourself (just tell the IdP to do it as part of startup scripts and warn you). I added a metadata query flow to 3.4 so it doesn't take much scripting to hit it with a few entityIDs to prime and send alerts if it doesn't have metadata on hand for that system. Prior, you'd just mock Unsolicited requests I imagine, but that's why I added the feature.

-- Scott