Our logging middleware listens for exceptions raised during a page view

and logs them, but this isn't always ideal. There are some exceptions

(Http404, PermissionDenied, and SuspiciousOperation) that Django

itself handles and logs (though in a log handler we currently don't use).

In the case of Http404, we really don't want to see the exception, as it's

not truly an error and just clutters up the log files.
This adds a list of exceptions to ignore, and also improves the current

exception logging to log additional information about the request.

Tested actual exceptions raised on a page and verified I could see the

logging information.
Tested Http404, PermissionDenied, and SuspiciousOperation

exceptions. Verified they did not invoke our logging.