mimic logrotate dateext
As ISPconfig is not using logrotate for the rotation of the logfiles in /var/log/ispconfig/http and uses the 1,2,3 naming schema, it is not possible to change that easily to a 'dateext' naming style. the benefit of dateext is that the files keep a consistent name and are not messing up the backups -> e.g. every day the data in mylog.1.gz "changes" because it gets replaced by the next new log file. With the dateext option mylog.20190512.gz always stays the way it is and will just get purged when it is old enough (or after X rotations). It would be nice if ISPconfig would "mimic" the dateext functionality (or even use logrotate).