pdns-common-4.0-bp155.4.6

- Modernize package:
  * switch to sysusers
  * don't buildrequire pkgconfig(systemd), that is only for programs building
    against libsystemd
  * remove bcond for systemd, we don't support any systems without systemd anymore
  * use %tpmfiles_create instead of raw call to systemd-tmpfiles
  * stop owning directories in /var/run (this is a tmpfs and rpms should not own
    anything inside there)

- initial package

- bsc#1130588: Require shadow instead of old pwdutils