sudo responder: new request enum type
    
    sss_sudo_type represents query type that comes to the responder
    sss_dp_sudo_type represents query type to DP that is issued by the responder
    
    I'm leaving current values of sss_dp_sudo_type untouched so the compilation
    is not broken. Hovewer, they will be changed to new DP types once the DP
    interface is updated.