Retake of service restarts (asg2023)

Stopping the old and starting a new service afresh -- that is what service restart is roughly about. We will look what it comprises in more detail from service manager perspective and also from the service's client end. Thus we will look at how FDSTORE API can be used to smooth service restart. Furthermore, we will review how unit instances may provide further distinction between the stopped and the restarted service. Finally, we go through options that the existing service have to adopt these methods. about this event: https://cfp.all-systems-go.io/all-systems-go-2023/talk/FYHCNJ/