Add a back/exit selection

src/freedombone-sec

 		   5 "Create a new Let's Encrypt certificate" off
 		   6 "Renew Let's Encrypt certificate" off
 		   7 "Enable GPG based authentication (monkeysphere)" off
-		   8 "Register a website with monkeysphere" off)
+		   8 "Register a website with monkeysphere" off
+		   9 "Go Back/Exit" on)
   choices=$("${cmd[@]}" "${options[@]}" 2>&1 >/dev/tty)
   clear
   for choice in $choices
 	  8)
 		register_website
 		;;
+	  9)
+		exit 0
+		;;
 	esac
   done
 }