Automatic merge from submit-queue

quota controller uses informers if available for pod calculation

This PR does the following:
1. plumb informer factory into quota registry and evaluators
2. pod quota evaluator uses informers for determining aggregrate usage instead of making direct calls
3. admission code path does not use informers because
   1. we do not want to add new watches in apiserver
   2. admission code path does not require aggregate usage calculation

As a result, quota controller is much faster in re-calculating quota usage when it observes a pod deletion.

Follow-on PRs will make similar changes for other informer backed resources (pvcs next).

/cc @deads2k @mfojtik @smarterclayton @kubernetes/rh-cluster-infra