Django middleware to send broken links to logger (vs standard send broken link by mail)

common.py

```
Django sends broken links by mail using built in middleware "BrokenLinkEmailsMiddleware".

This class alters that functionality and sends broken links to logger.
```

class BrokenLinkLogMiddleware(BrokenLinkEmailsMiddleware):
    def process_response(self, request, response):
        """Log broken link for relevant 404 NOT FOUND responses."""
        if response.status_code == 404 and not settings.DEBUG:
            domain = request.get_host()
            path = request.get_full_path()
            referer = request.META.get("HTTP_REFERER", "")

            if not self.is_ignorable_request(request, path, domain, referer):
                ua = request.META.get("HTTP_USER_AGENT", "<none>")
                ip = request.META.get("REMOTE_ADDR", "<none>")
                logger.warning('Broken %slink on %s, Referrer: %s, Requested URL: %s, User agent: %s, IP address: %s'
                             % (
                                 (
                                     "INTERNAL "
                                     if self.is_internal_request(domain, referer)
                                     else ""
                                 ),
                                 domain, referer, path, ua, ip
                             ))
        return response