Add ut cases of PodGroup util and improve controller integration about PodGroup #1784
Description
This PR #1506 is good for the use of PodGroup. And I'am be glad to improve its ut
UT：
1、mock dynamic.Interface using fake-client
2、test EnsurePodGroupExist and FinalizePodGroup logic
Integration:
1、add podgroup crd in config dir
2、add integration test cases on podgroup in podset and roleset with some common validation