Add try-runtime to Trappist (#239)

* Enable `try_execute_block` for try-runtime api

* Remove try-runtime from Stout runtime, otherwise this will cause a compile issue

Because Stout runtime is using the cumulus_ping pallet which does not have try-runtime feature.
See: https://github.com/paritytech/cumulus/issues/2704

* Remove try-runtime from Stout runtime, otherwise this will cause a compile issue

Because Stout runtime is using the cumulus_ping pallet which does not have try-runtime feature.
See: https://github.com/paritytech/cumulus/issues/2704

* Add try-runtime to Trappist runtime

* remove try-runtime from `stout`