Only report namespace mis-configuration once and not always
    
    Basically, instead of reporting that the namespace did not exist for
    every package/component in that namespace, we now only report it once
    per namespace (but we still print the full info in the logs if verbose
    is enabled).
    
    Then, instead of always emailing the admins for mis-configurations, we'll
    only email them if there are other errors then these which will happen
    all the time due to the flatpaks and tests namespaces which do not exist
    in PDC and bugzilla.
    
    Signed-off-by: Pierre-Yves Chibon <pingou@pingoured.fr>