Heap-allocated values in cross-context calls

After https://github.com/0xMiden/compiler/issues/111

We support scalar values (felt, integers) in function signatures in WIT. To support heap-allocated values (words, structs, etc.) in cross-context calls we need to implement lowering/lifting Wasm CM types for the Miden ABI for `call` op (pointers to stack/advice provider, etc. and back).