Additional elements added:
* monkit metric for observers methods like Start/Fork/Join/Finish to
be able to check how much time those methods are taking
* few more logs e.g. entries with processed range
* segmentsProcessed metric to be able to check loop progress
Change-Id: I65dd51f7f5c4bdbb4014fbf04e5b6b10bdb035ec
implemented observer and partial, created new structures to keep mon
metrics remain in same way as in segment loop
Change-Id: I209c126096c84b94d4717332e56238266f6cd004