Feature/cdodge/mongo perf tracker

Maintains a URL-># DB round trip mapping and dumps them to the log file periodically. This can be used to surface URLs that cause too many round trips to the database.

Right now we just turn on the middleware for the LMS since that gets most of the load

@cpennington @jarv -or - @e0d can you review, it'd be good to get a Dev and a DevOps person to look at this.