This update for systemd fixes the following issues:

- systemd.spec: use %sysusers_generate_pre so that some systemd users are
  already available in %pre. This is important because D-Bus automatically
  reloads its configuration whenever new configuration files are installed,
  i.e. between %pre and %post. (bsc#1248501)
  
  No needs for systemd and udev packages as they are always installed during
  the initial installation.

- Split systemd-network into two new sub-packages: systemd-networkd and
  systemd-resolved (bsc#1224386 jsc#PED-12669)