Improve help message for limiter/queue masks.
Improve help message for limiter/queue masks.

The user-facing most important change is that when setting masks on
Queues, we are not creating dynamic pipes (but queues).

The second change mentions that besides per-host bandwidth limits this
is helpful for per-subnet Queues/pipes.

This will need translation updates.

NewEraCracker/pfsense,pfsense/pfsense,phil-davis/pfsense,pfsense/pfsense,dennypage/pfsense,NewEraCracker/pfsense,pfsense/pfsense,phil-davis/pfsense,NewEraCracker/pfsense,dennypage/pfsense,pfsense/pfsense,NewEraCracker/pfsense,dennypage/pfsense,phil-davis/pfsense,dennypage/pfsense,phil-davis/pfsense