Add auto-annotation mutators on start up

[jefchien]

Issue #, if available: N/A

Description of changes:

• Adds auto-annotation configuration that gets passed in through auto-annotation-config flag.
• Adds auto-annotation mutators that get run at start up.
  • AnnotationMutator is partially based on kubectl annotate implementation (https://github.com/kubernetes/kubectl/blob/master/pkg/cmd/annotate/annotate.go#L457).
  • Has functions for each of the supported resources.
• Adds unit tests for annotation mutators.

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