Add domains per user binning to stats page, add missing image
<Admin::Suggestion> generate unique id

We need an ID to identify each suggestion; it should stay the same when
serialized, however, so that it can be used to look up "the same"
suggestion across different requests.
<admin-console> first rough draft of suggestions

suggestions controller and views created.
no tests, lots of work to do.
<DO NOT MERGE> enable testing locally