Add support for Rust bindings

[codespree]

The idea here is to generate safe, ergonomic, bindings from the UDL for a Rust consumer module (like Swift, Kotlin, Python, Ruby).

That module then invokes the methods through FFI - exposing a type-safe Rust interface.

This will allow Rust developers to generate and distribute closed source libraries written in Rust which can be consumed from Rust without resorting to plumbing such as:

1. abi_stable - https://docs.rs/abi_stable/latest/abi_stable/
2. Stabby - https://github.com/ZettaScaleLabs/stabby

Also, given the current state of the project, generating Rust bindings might be relatively easier than the other bindings that this project already produces.