[server] Initialize Repository without a tasks manager in ServerMigrationHelper.restore_database() We don't need a tasks manager here I think. Thus instantiate the Repository from its class directly instead of using config.repository() which set a tasks manager.

missing-dep-for-interpreter make => make | build-essential | dpkg-dev (usr/*/cubicweb/skeleton/debian/rules)
embedded-javascript-library usr/share/cubicweb/cubes/shared/data/jquery.js