add options winston_logging_maxfiles{maxsize,maxfiles} to get some log rotation

This is a dead-end change to the train-2013.10.09, since the logging code changes significantly after that point in time. This is to address the current lack of log rotation in producition. (However, the current production branch is train-2013.10.09 plus some security fixes, so this PR may not be used, depending on which repo is used to ship this change). See https://github.com/mozilla/identity-ops/issues/126 for other comments.