Migrate to controller-runtime logger

[tenzen-y]

Currently, the training-operator uses some types of logger like this:

• sirupsen/logrus logger:

  training-operator/pkg/util/logger.go

  Line 85 in c204220

  func LoggerForUnstructured(obj *metav1unstructured.Unstructured, kind string) *log.Entry {

• controller-runtime logger:

  training-operator/cmd/training-operator.v1/main.go

  Line 111 in c204220

  ctrl.SetLogger(zap.New(zap.UseFlagOptions(&opts)))

So, based on this discussion, I'd like to suggest using the controller-runtime logger everywhere to increase maintainability and consistency.

[champon1020]

Could I work on this task?

[tenzen-y]

@champon1020 Sure, Feel free to assign yourself with a /assign comment.

[champon1020]

/assign