Move floodgate to middleware, add extender + integration tests (#2170)

tests/integration/api/authentication/WithApiKeyTest.php

@@ -28,6 +28,9 @@ class WithApiKeyTest extends TestCase
                 $this->adminUser(),
                 $this->normalUser(),
             ],
+            'group_permission' => [
+                ['permission' => 'viewUserList', 'group_id' => 3]
+            ],
             'api_keys' => [],
         ]);
     }