SCORU/Node: types necessary to build smart rollup operations

Context

This MR introduces common base types for structures used in SCORU operations (commitments, inboxes, dissections, etc.) with conversions with their respective protocol implementation.

It is necessary for the protocol agnostic node, in particular for moving the injector outside of proto_* (by having a common representation for operations).

Depends on !8625 (merged) and !8989 (merged).

Manually testing the MR

dune exec tezt/tests/main.exe -- -f test_octez_conversions.ml