Proper parameters for prizegroup forms

Previous implementation was really quick and dirty one done during Assembly summer 2014, this one respects the framework.
BUGFIX: we used to delete one slide too many...

We checked for awards.size slides and deleted the excess PrizeSlides, but we also need one slide for the "empty" first slide that only shows the competition tittle.
Remove the half-implemented rrd monitoring and logging

We have a half-implemented rrd data logging in lib/monitoring.rb now we don't require it or the the rrd-gem.