IcingaConfig: allow to toggle legacy renderer

refs #12264

library/Director/IcingaConfig/IcingaConfig.php

@@ -35,7 +35,7 @@ class IcingaConfig
 
     protected $generationTime;
 
-    protected $configFormat = 'v2';
+    protected $configFormat;
 
     public static $table = 'director_generated_config';
 
@@ -46,6 +46,7 @@ class IcingaConfig
 
         $this->connection = $connection;
         $this->db = $connection->getDbAdapter();
+        $this->configFormat = $this->connection->getSetting('config_format', 'v2');
     }
 
     public function getSize()

library/Director/Objects/IcingaObject.php

@@ -1151,6 +1151,10 @@ abstract class IcingaObject extends DbObject implements IcingaConfigRenderer
 
     public function renderToConfig(IcingaConfig $config)
     {
+        if ($config->isLegacy()) {
+            return $this->renderToLegacyConfig($config);
+        }
+
         if ($this->isExternal()) {
             return;
         }