More systemd service management cleanup

More systemd service management cleanup

Please see discussion at:
https://github.com/systemd/systemd/issues/8096

The new approach is:

 * non-templated kresd.socket and kresd-tls.socket, for the
   public-facing listening ports.  They know to invoke kresd@1.service
   if they're socket-activated.

 * kresd@.service *is* templated, to allow the admin to add more
   concurrent runners with:

      systemctl enable kresd@2.service

 * kresd-control@.socket is still templated, since each daemon has a
   separately-addressable different control port.

 * non-templated kresd.service is a dummy meta-service.  it is in the
   same slice as kresd@.service, and all the kresd@.service instances
   are PartOf= it, so you should be able to stop and restart all
   services together.  On systems like debian that ship
   /etc/init.d/kres, this also avoids having systemd-sysv-generator
   create a kresd.service based on the initscript.

 * no templated instances are explicitly instantiated during initial
   ship, but kresd@1.service should be socket-activated cleanly

Gbp-Pq: Name 0010-More-systemd-service-management-cleanup.patch