scripts/install-systemd-multi-user.sh: install /etc/tmpfiles.d/nix-daemon.conf, too
scripts/install-systemd-multi-user.sh: install /etc/tmpfiles.d/nix-daemon.conf, too

While `create_directories()` from install-multi-user.sh seems to already
create parts of the directory structure, it's marked as deprecated, and
it won't hurt also copying over the tmpfiles config and have it execute
once.

NixOS/nix,rycee/nix,NixOS/nix,NixOS/nix,rycee/nix,rycee/nix,rycee/nix,NixOS/nix,rycee/nix,NixOS/nix