MDL-25290 conversion: Converted config to use MUC

lib/db/caches.php

@@ -75,4 +75,15 @@ $definitions = array(
         'datasource' => 'question_finder',
         'datasourcefile' => 'question/engine/bank.php',
     ),
+
+    // Used to store data from the config + config_plugins table in the database.
+    // The key used is the component:
+    //   - core for all core config settings
+    //   - plugin component for all plugin settings.
+    // Persistence is used because normally several settings within a script.
+    'config' => array(
+        'mode' => cache_store::MODE_APPLICATION,
+        'persistent' => true,
+        'simpledata' => true
+    ),
 );