phase-shelve: Implement a 'shelve.store' experimental config
Accepts "internal" or "strip", indicating how the shelved changes are stored. Defaults to "internal", retaining compatibility for repos with "internal-phase" already enabled.
{
"conduit_uri": "https://phab.mercurial-scm.org/api",
"phabricator.uri": "https://phab.mercurial-scm.org/",
"repository.callsign": "HG",
"arc.land.onto.default": "@",
"base": "hg:.^"
}