Lib_scoru_wasm: Module decoders/encoders

Context

This MR Introduces a module Wasm_encoding that replaces the current module Wasm_decodings with one that exposes AST ecnoder/decoders.

Dependencies:

• More tree-encoders/decoders !5892 (merged)
• Refactor host-funcs !5920 (merged)
• AST pretty printers and QCheck generators !5953 (merged)

Manually testing the MR

There are currently some tests failing due to issues with Interpreter_encodings. Working to resolve that.

dune exec src/lib_scoru_wasm/test/test_scoru_wasm.exe 

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