Reverse of IdP Discovery Service

[Klingenstein, Nate]

> But if there's really some sort of demand for "give it an entityID and get back a page with some basic UI customization based on the metadata and a link to initiate SSO to it", file an RFE

I can't guarantee anyone else cares about it or I got it right, but:

https://issues.shibboleth.net/jira/browse/IDP-1250

Several of our campuses would probably use the feature immediately, but I don't expect priority until we're members.