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

tool, updated for modern handling of ExceptionGroup

libp2p/tools/async_service/stats.py

@@ -0,0 +1,18 @@
+# Copied from https://github.com/ethereum/async-service
+
+from typing import (
+    NamedTuple,
+)
+
+
+class TaskStats(NamedTuple):
+    total_count: int
+    finished_count: int
+
+    @property
+    def pending_count(self) -> int:
+        return self.total_count - self.finished_count
+
+
+class Stats(NamedTuple):
+    tasks: TaskStats