Binding against Miden procedures from Rust

Currently, the compiler understands how to generate the necessary glue code for the Miden FFI (foreign-function interface). It does so based on having a type signature and a known calling convention/ABI. However, this is currently restricted to a hardcoded whitelist of known Miden Assembly procedures and their corresponding signatures.

We want to remove this manually-maintained list of procedures, and open up the FFI to any procedure implemented in Miden Assembly. However, in order to do so, we need to be able to obtain the signature/calling convention/ABI from metadata, which currently doesn't exist anywhere.

This is a tracking issue for the implementation of this feature