Add and use optimized http log syncing script
    
    The previous one synced all hosts serially and ran rsync for each log
    file. This reimplements the shell script in Python, with these changes:
    
    - Run rsync on whole directories of log files, with much reduced
      overhead.
    - Use a pool of five workers which process hosts in parallel.
    
    Additionally, remove download-rdu01.vpn.fedoraproject.org from the list
    of synced hosts.
    
    Signed-off-by: Nils Philippsen <nils@redhat.com>