Include contributors and groups in the people watching bugs in bugzilla
    
    Basically we were only including the POC and people who set their watch
    access correctly, but contributors are supposed to be looking at issues
    by default, they can then opt-out using 'unwatch'.
    Groups were simply entirely ignored while they are present also in the
    list of watchers.
    
    Signed-off-by: Pierre-Yves Chibon <pingou@pingoured.fr>