Rotate zuul logs with logrotate

Python logrotate does not compress. Use logrotate utility to do log
rotation so that older logs can be compressed saving disk space.

Change python logging to use normal file handlers as it will no longer
be doing the rotation for us. Keep all the file names the same.

Change-Id: I7302e4b197e99fd49fd9d5678702333b17a46efa
Merge "Rotate zuul logs with logrotate"