Split scaffolding script (#26832)

* Add scaffolding split

* Add second config flow method

script/scaffold/error.py

@@ -4,7 +4,7 @@
 class ExitApp(Exception):
     """Exception to indicate app should exit."""
 
-    def __init__(self, reason, exit_code):
+    def __init__(self, reason, exit_code=1):
         """Initialize the exit app exception."""
         self.reason = reason
         self.exit_code = exit_code