The interval of the background health checker needs to be configurable

YUNIKORN-1107 adds a background running health checker to verify the scheduler data correctness in the fixed time interval 30s: https://github.com/apache/yunikorn-core/blob/3ba91fb8a41c0fd0dd6243326e583dea5167199f/pkg/scheduler/health_checker.go#L34. We need to make this configurable, either let the user set a longer/shorter interval, or completely disable it.