Fix unique generation of ActorNames

[johanneshiry]

On very large datasets the current implementation of the actor naming uuid tends to be not unique anymore. Therefore we need to find an alternative for the unique name generation.

Possible approaches:

• remove substring(0,8) (might clutter logs...)
• find another method to generate unique identifiers (maybe hash values?

Affected line:

[t-ober]

The system participants are built with

    def simonaActorOf(props: Props, actorId: String): ActorRef =
      refFactory.actorOf(props, actorName(props, actorId))

where the actorId is used. Find out what we want here.

[sebastian-peter]

Ids (which are name-like a lot of times, in my experience) have to be unique as well, maybe that's a way to consider?