Proto/SCORU: carbonated Sc_rollup_commitment_repr.hash

Context

Partly answers #3291 (closed).

The carbonated version of Sc_rollup_commitment_hash_repr hashing is put in Sc_rollup_commitment_storage because this is the place that makes the more sense to me above Raw_context, where gas consumption is defined.

Manually testing the MR

The regression trace updates show it all.

Checklist

• Document the interface of any function added or modified (see the coding guidelines)
• Document any change to the user interface, including configuration parameters (see node configuration)
• Provide automatic testing (see the testing guide).
• For new features and bug fixes, add an item in the appropriate changelog (docs/protocols/alpha.rst for the protocol and the environment, CHANGES.rst at the root of the repository for everything else).
• Select suitable reviewers using the Reviewers field below.
• Select as Assignee the next person who should take action on that MR