Prune Users based on email address or other "user name contains" field

[kh99]

Yeah, I've been thinking about it because this is something that's asked a lot. I think the most frustrating part is that the search functions exist in the "Search For Users" code, but you can't do anything from there except one user at a time. But it seems like there should be some relatively easy way to use the "Search for Users" results for the "Move/Prune Users" page.