Improved outage class encapsulation. Added outagedb as DB Context. Other minor changes.

auth.php

@@ -35,6 +35,13 @@ require_once($CFG->libdir . '/authlib.php');
  */
 class auth_plugin_outage extends auth_plugin_base
 {
+    /**
+     * Constructor.
+     */
+    public function __construct() {
+        $this->authtype = 'outage';
+    }
+
     /**
      * Do not authenticate users.
      * @return bool False