reduce the number of times we hit qmore.client for config

Makes sure we don't git qmore for every client each time. Instead only hit it for the each client we attempt to pull a job from.

More work needs to be done here.
prioritize_queues(get_priority_buckets, matched_names)
and
expand_queues(regexes, queue_names)
Are extremely expensive at scale due to the number of times we call them.
Preferably we'd cache the configuration stored in qless and update it periodically.