SCORU: Wasm PVM: implement store_has

Context

• Fixes #3538 (closed)
• Part 3 of !6228 (merged)
• Depends on !6301 (merged)
• Depends on trili/kernel!64

Implement store_has host capability. It can return the following depending on the value of the path:

#[repr(C)]
enum ValueType {
  None, // 0
  Value, // 1
  Subtree, // 2
  ValueAndSubtree // 3
}

Manually testing the MR

dune exec  src/lib_scoru_wasm/test/test_scoru_wasm.exe \
                    -- test "Durable storage"

dune exec  src/lib_scoru_wasm/test/test_scoru_wasm.exe \
                    -- test "^WASM PVM$"

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