LAS-87 first steps towards load balancing

Executes a service on a random node (among the nodes running the
service)
BUT: Currently invocations are all executed synchroniously, so there is
no speed advantage yet.
LAS-87 functional load balancing

works and uses fallbacks (so nothing should break)
more robust service Information storage across multiple envelopes
service registration attempts limitted to 3

service tries to register itself within the network several times (3 by
default). This is to avoid problems when connecting nodes.
Merge remote-tracking branch 'origin/loadBalancing'