Feature flags (#543)

* Re-organize a bit controllers

* Added the featureflagcontroller

* Implement feature flags in the front-end

* Clean env files

* Clean console.log messages

* Fix feature flag test

api/app/Http/Controllers/Content/SitemapController.php

@@ -0,0 +1,31 @@
+<?php
+
+namespace App\Http\Controllers\Content;
+
+use App\Models\Template;
+use Illuminate\Http\Request;
+use App\Http\Controllers\Controller;
+
+class SitemapController extends Controller
+{
+    public function index(Request $request)
+    {
+        return [
+            ...$this->getTemplatesUrls(),
+        ];
+    }
+
+    private function getTemplatesUrls()
+    {
+        $urls = [];
+        Template::where('publicly_listed', true)->chunk(100, function ($templates) use (&$urls) {
+            foreach ($templates as $template) {
+                $urls[] = [
+                    'loc' => '/templates/' . $template->slug,
+                ];
+            }
+        });
+
+        return $urls;
+    }
+}