narrow: use `get_unique_pull_path` The narrow's `tracked` command does not support multiple destination, lets use the dedicated API then. Differential Revision: https://phab.mercurial-scm.org/D10404

urlutil: add a new `get_unique_pull_path` This function is dedicated to call that needs a single destination. Currently most caller actually need that since few actually support multiple destinations (the most importants `hg push` and `hg outgoing` do). So having a clear API point for that will be important when the time comes to have a single `[paths]` alias resolving to multiple urls. Differential Revision: https://phab.mercurial-scm.org/D10403

mq: use the new `get_clone_path` to get the remote url We stop using `ui.expandpath` to use a function with a more defined semantic. This will help us to make it an option to point [paths] entry to multiple destination. Differential Revision: https://phab.mercurial-scm.org/D10402

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