Refactor templates to be more structured

src/Controller/SnipController.php

@@ -132,7 +132,7 @@ class SnipController extends AbstractController
             return $this->redirectToRoute('snip_index');
         }
 
-        return $this->render('form.html.twig', [
+        return $this->render('generic/form.html.twig', [
             'message' => sprintf('Do you really want to delete "%s"?', $snip),
             'form' => $form->createView(),
         ]);