- move extender related API from pkg/scheduler/api to pkg/scheduler/apis/extender/v1
- alias extenderv1 to pkg/scheduler/apis/extender/v1
- use NodeScore and NodeScoreList in non-extender logic
- Rename 'topologyPairsPodSpreadMap' to 'podSpreadCache'
- New struct `criticalPaths criticalPaths`
- Add unified method `*criticalPaths.update()` for:
- regular update
- addPod in preemption case
- remotePod in preemption case