refactor scheduler extender related API

- 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

pkg/scheduler/scheduler_test.go

@@ -144,8 +144,8 @@ func PredicateOne(pod *v1.Pod, meta predicates.PredicateMetadata, nodeInfo *sche
 	return true, nil, nil
 }
 
-func PriorityOne(pod *v1.Pod, nodeNameToInfo map[string]*schedulernodeinfo.NodeInfo, nodes []*v1.Node) (schedulerapi.HostPriorityList, error) {
-	return []schedulerapi.HostPriority{}, nil
+func PriorityOne(pod *v1.Pod, nodeNameToInfo map[string]*schedulernodeinfo.NodeInfo, nodes []*v1.Node) (framework.NodeScoreList, error) {
+	return []framework.NodeScore{}, nil
 }
 
 type mockScheduler struct {