horizon does not log requests to itself in it's main log

Currently (7.0 and below) Horizon log is split into several files, which makes troubleshooting cumbersome.
As of 7.0, there is /var/log/horizon/horizon.log which contains debug data if debug is enabled and is mostly empty otherwise, and there is also /var/log/apache2/horizon_access.log and /var/log/apache2/horizon_error.log.

The problem with the main log /var/log/horizon/horizon.log is that it does not contain info about the actual requests to Horizon. Such information is only available in apache log, but is also incomplete for debugging purposes - for troubleshooting it is important to see both START and END timestamps for each request, apache log only provides one log line with one timestamp per request.

Please add logging functionality which will allow to see incoming requests in main horizon log, as well as the timestamp for when reply is sent. Such info is visible for all the OpenStack clients inside this log except Horizon itself.