Propagate all labels from template

When user specifies labels in the template section, they should be propagated even when they are app.kubernetes.io labels (or at least some of them). For example in this case:

    template:
      statefulset:
        metadata:
          labels:
            app: spring-music-cdc
            app.kubernetes.io/part-of: spring-music-cdc
            template: spring-music-cdc

Here the app.kubernetes.io/part-of label should be propagated to indicate what application is this part of. This should not apply to any strimzi.io labels which are our own.

Related to Strimzi#2743