Add option to set queue prioritizer on process group level

I'm looking for the way to set queue prioritizer for all queues in PG on group level to avoid setting it in each particular queue in PG. 

For now it's not possible, so it is painful, if someone miss to set it in new queue in PG, where it plays important role.

My expectations if PriorityAttributePrioritizer is set on PG level - if priority attribute is set, PriorityAttributePrioritizer will be used, otherwise it'll work as usual - FIFO.