Linking to datastream fcr:metadata in HTML UI

Fixes https://www.pivotaltracker.com/story/show/80952408
We could indeed add a javascript handler to do a HEAD request and redirect based on that.  And that's basically what we're doing in the message consumer.  But that seems much less desirable to me than just updating the HTML template to include the children by default.

I understand not wanting to have the children included for all REST API calls, but IMHO the HTML view is already different enough anyway that I wouldn't necessarily expect them to be triple-for-triple identical anyway.