Removes a couple of unused/broken scripts from`rule-schema-to-typescript-types`.Also adds a missing nx target such that `generate-breaking-changes`works again.

This switches various repo scripts to be `*.mts` files (since that iswhat they actually are, given we don't build them into CJS output, yetour package `type` is `"commonjs"`).This will allow newer Node to execute them correctly, as they will nowinfer the correct module type.The `generate-lib` script has also been changed to use only strippabletypes (i.e. no enums).Both of these changes mean we have the option to drop `tsx` in futureand use `--experimental-strip-types` (when it is no longerexperimental).

Drops `tsx` and uses `--experimental-strip-types` to directly executethe various typescript scripts we have.We likely don't want to land this until it is no longer "experimental".