Attempt to start libvirtd.service on install on Debian/Ubuntu if enabled
    
    The unique characteristics of the libvirtd service with its chain of
    socket activated units alongside the initial startup of the main service
    make it quite difficult to activate through configuration management
    systems, so we will handle it here as a special case. However,
    this behavior is consistent with how services are generally handled
    on Debian/Ubuntu systems anyway.