contracts: Move `Schedule` from Storage to `Config` (#8773)

* Move `Schedule` from Storage to Config

* Updated CHANGELOG

* Fix nits from review

* Fix migration

* Print the debug buffer as tracing message

* Use `debug` instead of `trace` and update README

* Add additional assert to test

* Rename `schedule_version` to `instruction_weights_version`

* Fixed typo

* Added more comments to wat fixtures

* Add clarification for the `debug_message` field