urlutil: introduce a new `list_paths` function This function will be useful for command and template that wants to display path related information. Differential Revision: https://phab.mercurial-scm.org/D10440

{
    "conduit_uri": "https://phab.mercurial-scm.org/api",
    "phabricator.uri": "https://phab.mercurial-scm.org/",
    "repository.callsign": "HG",
    "arc.land.onto.default": "@",
    "base": "hg:.^"
}