make identify an abstract module method

Author: ahiuchingau

Diff for: api/src/opentrons/hardware_control/modules/mod_abc.py

@@ -224,3 +224,7 @@ async def cleanup(self) -> None:
         object destruction.
         """
         pass
+
+    async def identify(self) -> None:
+        """Identify the module."""
+        pass