Proto,SCORU: if the whitelist exists check that the submitter of a commitment is in it

Context

Implements the logic for restricting the publishing of new commitments to members of a whitelist if it exists and the private rollup feature is activated.

Manually testing the MR

dune exec src/proto_alpha/lib_protocol/test/integration/operations/main.exe -- --file test_sc_rollup.ml

dune exec tezt/tests/main.exe -- --file sc_rollup.ml "whitelist"

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