Define interfaces for common job operators

[jian-he]

Creating the interfaces for custom controllers to implement, that is:

	// DeleteJob deletes the job
	DeleteJob(job interface{}) error

	// UpdateJobStatus updates the job status and job conditions
	UpdateJobStatus(job interface{}, replicas map[common.ReplicaType]*common.ReplicaSpec, jobStatus common.JobStatus) error

	// CreateService creates the service
	CreateService(job interface{}, service *v1.Service) error

	// DeleteService deletes the service
	DeleteService(job interface{}, service *v1.Service) error

	// CreatePod creates the pod
	CreatePod(job interface{}, podTemplate *v1.PodTemplate) error

	// DeletePod deletes the pod
	DeletePod(job interface{}, pod *v1.Pod) error

	// SetClusterSpec sets the cluster spec for the pod
	SetClusterSpec(job interface{}, podTemplate *v1.PodTemplate, rtype, index string) error
}

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This change is 

@richardsliu @johnugeorge @terrytangyuan

[gaocegege]

/lgtm

I love this change! Thanks

[terrytangyuan]

Looks great. Thanks!
/lgtm

[richardsliu]

/lgtm

[johnugeorge]

/lgtm

[johnugeorge]

/approve

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