urlutil: add a `get_clone_path` function We add a new function with a semantic focussed on `clone` operation (so without an existing repository). I am not certain the return type is the best, but this is what we need for now. Once all caller are migrated we might start thinking about that the API should be. For now that will do. Differential Revision: https://phab.mercurial-scm.org/D10401