Sort public inputs by name

To guarantee consistent results and to prevent bugs because of refactoring code, i.e. moving the definition order of public input column, a stable order of the public input columns is useful. The proposed approach is to sort the column by name, so a user is allowed to move the definition in the text file without causing breakage, and this would also prevent differences among the different backends.

Context:

- https://github.com/0xPolygonMiden/air-script/pull/301#discussion_r1229065366
- https://github.com/0xPolygonMiden/air-script/pull/301#discussion_r1210902893