remove AppFeature and all references to it in the code/tests (#1893)

* remove AppFeature and all references to it in the code/tests

Co-authored-by: bmccandless <bmccandless@chanzuckerberg.com>

server/test/unit/common/test_api.py

@@ -49,7 +49,6 @@ class EndPoints(object):
         result_data = result.json()
         self.assertIn("library_versions", result_data["config"])
         self.assertEqual(result_data["config"]["displayNames"]["dataset"], "pbmc3k")
-        self.assertEqual(len(result_data["config"]["features"]), 5)
 
     def test_get_layout_fbs(self):
         endpoint = "layout/obs"