Refactor the descheduler code base to allow a quick implementation of the proposal in https://github.com/kubernetes-sigs/descheduler/pull/1354.

DoD:

• extend the PodEvictor with a ResetCounters so it can be initialized only once outside of the descheduling cycle: https://github.com/kubernetes-sigs/descheduler/pull/1447
• ( ) generate UID for test pods: https://github.com/kubernetes-sigs/descheduler/pull/1454