Finish informer work

[hongchaodeng]

Since upstream provides good examples of informer for CRD, we made use of that and already switched our watching code to informer. But some work is left to be done:

• use generated informer
• Use workqueue. Nothing should block event handler.
• here converts the informer event to internal event. We shouldn't need the duplicate events. Should clean it up . Otherwise it is confusing.