systemd-init: choose util-linux-login

[xnox]

Debian trixie, AL2023, fedora all use PAM enabled util-linux-login, instead of shadow or busybox one.

Also busybox one doesn't work with selinux-refpolicy, as most policies do not allow symlink for login by default.

Also remove duplicate agetty.

Choose util-linux-login as the preffered login binary.