Add T&C's accept to start of USSD flow

New users should see:

    To proceed with registration, do you accept the Terms & Conditions of Ni Nyampinga (link):
    1. Yes 
    2. No

If they select Yes should go to next question on gender. If No, end state with "Sorry but we can't proceed with your registration unless you accept the Terms & Conditions. Please redial if you change your mind. Thanks!"