BibSched: post process params

These patches to the scheduler is required for INSPIRE Labs when setting up the synchronization with Production machines to know when records pushed from Labs to Production is processed on Production.

I would like to add it to pu because (a) it may end up in master, and (b) for our own testing locally with the round-trip via two instances of Invenio. Otherwise, we'll have to keep these on our Labs branch for `pu` (less desirable of course).

*PS: This is also part of INSPIRE prod branch running on master. This is the next port of those patches.*