drop async-service dep and copy relevant code into a local async_service

tool, updated for modern handling of ExceptionGroup

libp2p/tools/async_service/__init__.py

@@ -0,0 +1,15 @@
+from .abc import (
+    ServiceAPI,
+)
+from .base import (
+    Service,
+    as_service,
+)
+from .exceptions import (
+    DaemonTaskExit,
+    LifecycleError,
+)
+from .trio_service import (
+    TrioManager,
+    background_trio_service,
+)