feat: cairo_run for functions in namespaces

[ClementWalter]

Given a cairo file like

namespace Foo {

    func bar() {
        return ();
    }
}

the cairo_run should use

cairo_run("Foo.bar", ...)

[ClementWalter]

Blocked by incorrect types in some sw corelibe

starkware.cairo.lang.compiler.preprocessor.preprocessor_error.PreprocessorError:
/home/runner/work/keth/keth/.venv/lib/python3.10/site-packages/starkware/cairo/common/cairo_secp/signature.cairo:149:20: Expected expression of type 'starkware.cairo.common.cairo_secp.bigint3.SumBigInt3', got 'starkware.cairo.common.cairo_secp.bigint3.BigInt3'.
E                   return is_zero(reduced_diff);

[Eikix]

Should we close this PR for now and come back later to it?
I can also convert it into a P2 issue