Refactor interop tests and factories

- Add `close` and `disconnect` in `Host`
- Add `close` and `close_peer` in `Network`
- Change `IListener.close` to async, to await for server's closing
- Add factories for security transports, and modify `HostFactory`

tests/pubsub/test_gossipsub_backward_compatibility.py

@@ -2,8 +2,9 @@ import functools
 
 import pytest
 
+from tests.factories import GossipsubFactory
+
 from .configs import FLOODSUB_PROTOCOL_ID
-from .factories import GossipsubFactory
 from .floodsub_integration_test_settings import (
     floodsub_protocol_pytest_params,
     perform_test_from_obj,