feat: add instance config endpoint

src/Controller/InstanceController.php

@@ -0,0 +1,20 @@
+<?php
+
+namespace App\Controller;
+
+use App\Entity\Instance;
+use Symfony\Bundle\FrameworkBundle\Controller\AbstractController;
+
+class InstanceController extends AbstractController
+{
+    public function __invoke(): Instance
+    {
+        $instance = new Instance();
+
+        $instance
+            ->setLimitedFeatures($this->getParameter('limited_features') ?? false)
+            ->setOauthEnabled($this->getParameter('oauth_enabled'));
+
+        return $instance;
+    }
+}