[algo] in EventBuildChain, add publication of Histos to server

DISCLAIMERS:
1) emission happens on every iteration of the main loop over TS!
=> No memory between iterations to accumulate statistics
=> No limitation (time interval or nb iterations interval) on emission, lots of small TS will lead to lots of messages emission
2) ZMQ addressing hardcoded in header, would need to be added to binary arguments and maybe also to YAML config!