+clu #3149: Gossip boosting

*DO NOT MERGE*

This is a quick'n'dirty implementation of boosting the propagation of gossip messages when they are still very fresh. Things missing:
 - proper testing (it passes the cluster tests on my machine, but that just proves that the gossip is not broken, not that it does what I want it to ;) )
 - measurements and validation
 - cleanup (this is just a hacky PoC for initial experiments)
 - tuning (this optimization is supposed to shine on larger clusters, so it should be probably toned down or disabled for smals clusters)