Add custom email for 2FA

Related #1490

src/Wallabag/UserBundle/DependencyInjection/Configuration.php

@@ -0,0 +1,17 @@
+<?php
+
+namespace Wallabag\UserBundle\DependencyInjection;
+
+use Symfony\Component\Config\Definition\Builder\TreeBuilder;
+use Symfony\Component\Config\Definition\ConfigurationInterface;
+
+class Configuration implements ConfigurationInterface
+{
+    public function getConfigTreeBuilder()
+    {
+        $treeBuilder = new TreeBuilder();
+        $rootNode = $treeBuilder->root('wallabag_user');
+
+        return $treeBuilder;
+    }
+}

src/Wallabag/UserBundle/DependencyInjection/WallabagUserExtension.php

@@ -0,0 +1,25 @@
+<?php
+
+namespace Wallabag\UserBundle\DependencyInjection;
+
+use Symfony\Component\DependencyInjection\ContainerBuilder;
+use Symfony\Component\Config\FileLocator;
+use Symfony\Component\HttpKernel\DependencyInjection\Extension;
+use Symfony\Component\DependencyInjection\Loader;
+
+class WallabagUserExtension extends Extension
+{
+    public function load(array $configs, ContainerBuilder $container)
+    {
+        $configuration = new Configuration();
+        $config = $this->processConfiguration($configuration, $configs);
+
+        $loader = new Loader\YamlFileLoader($container, new FileLocator(__DIR__.'/../Resources/config'));
+        $loader->load('services.yml');
+    }
+
+    public function getAlias()
+    {
+        return 'wallabag_user';
+    }
+}