MDL-39412 disabling manual graded behaviour refinements

1. Change behaviour admin settings so you can only select enabled
behaviours.
2. During the upgrade, change admin settings that might be currently set
to manual graded, so that instead they are set to deferredfeedback (if
that is available. If not, we just take the first alphabetically.)

lib/adminlib.php

@@ -4142,7 +4142,7 @@ class admin_setting_question_behaviour extends admin_setting_configselect {
     public function load_choices() {
         global $CFG;
         require_once($CFG->dirroot . '/question/engine/lib.php');
-        $this->choices = question_engine::get_archetypal_behaviours();
+        $this->choices = question_engine::get_behaviour_options();
         return true;
     }
 }