Allow for transitive modules using `module_path!` macro.

[kpob]

If you are in the examples directory and build Erc20 module by calling ODRA_MODULE=Erc20 cargo build --bin odra_examples_build_contract --target wasm32-unknown-unknown you will get a valid contract, even though the Erc20 is implemented in modules not in examples

[zie1ony]

We change the scope of this task to actually allow transitive modules using full paths.