order the type alphabetically

Improve also the form "TranslatableActivityType" to use the
TranslatableStringHelper.

DependencyInjection/ChillActivityExtension.php

@@ -47,6 +47,7 @@ class ChillActivityExtension extends Extension implements PrependExtensionInterf
 
         $loader = new Loader\YamlFileLoader($container, new FileLocator(__DIR__.'/../Resources/config'));
         $loader->load('services.yml');
+        $loader->load('services/repositories.yml');
     }
     
     public function prepend(ContainerBuilder $container)