Add 'nix-name and 'system properties to hydra objects. This way Cuirass won't have to go through every derivation to add those properties. * gnu/ci.scm (package->alist, image-jobs, system-test-jobs, tarball-jobs): Add 'nix-name and 'system properties. * build-aux/hydra/guix-modular.scm (build-job): Ditto.