Scoru,Fast: kernel caching mechanism for fast execution

Context

see #4122 (closed)

Fast execution parses the kernel at each compute call by way of Wasmer.Module.create. This proposal implements a caching mechanism to retain the modules created, indexed by the hash (tree hash ?) of the kernel.

A simple cache mechanism is added, and instantiated in a Module_cache that exposes a function to load module, given a Wasmer store and a key in a durable storage.

Manually testing the MR

dune exec src/lib_scoru_wasm/test/test_scoru_wasm.exe -- test "^Fast Execution cache$"

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