SCORU: Wasm PVM: add durable storage wrapper

Context

• Related: #3538 (closed).
• Part 1 of !6228 (merged)

Add a durable storage wrapper, which turns wrapped_tree into a tree of chunked_byte_vectors, with additional constraints on the key type (only ascii-alphanumeric, or dots; bounded in length).

Manually testing the MR

CI

dune exec src/lib_scoru_wasm/test/test_scoru_wasm.exe

dune exec src/proto_alpha/lib_protocol/test/integration/main.exe -- test "^sc rollup wasm$"

dune exec tezt/tests/main.exe -- --file sc_rollup.ml wasm_2_0_0

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