Admin improvements [RD-46]

I sent this off to Seth to see if he wanted to do some usability testing. In the meantime, I thought I would see if anyone had suggestions for the bits that aren't user-visible.

The DestinationManipulation section works pretty well, allowing you to search by buid and view source and/or select multiple actions to view.

The Redirect section does not work nearly as well. As I mentioned in the ticket, this takes way too long to run. I've limited myself to improving what is displayed once it loads as any searching/filtering will just increase the load time.