feat: group admin sidebar items into single Administration page with action cards

src/Controllers/AdminController.php

@@ -37,6 +37,13 @@ class AdminController
         }
     }
 
+    public function index(): void
+    {
+        $this->view->display('admin.index', [
+            'title' => 'Administration - ServerManager',
+        ]);
+    }
+
     public function users(): void
     {
         $this->requireSuperAdmin();