update stats with information about task in crab3 related to McM

This is standalone for the moment.
The getter might have to be factorized out to the central getter, with the change to the header argument, which does matter for the crabserver.
This could be included in driveUpdate.py as part of the code under "update" with

from crabUpdate import updateCycle
updateCycle()

needs changes in McM requests schema (private member) and lucene search (search on private) to fully function.