Renamed migrations.
Code review feedback.
Commented the code as part of code review.
Removed dependencies between jobs.

We are not really using them. We are mostly using that all jobs relate
to the same publication. Moreover, this now allows that spawned jobs
are processed immediately (if there are multiple worker instances) or
at least that if parent job fails at the end (or process is killed),
spawned jobs will still be done.
Refactored code and fixed edge cases.

This is a followup to #520. validateArgument arguments were switched in
order so that it is possible to write Match.Where condition function
without parenthesis. Moreover, in set-role-for-group and
set-role-for-person there should still be check.
Updated to new validateArgument.