Allow add annotations/labels on private key creation/rotation

Which component: controller

Is your feature request related to a problem? Please describe.

Actually, the private key creation/rotation function does not allow us to include any kind of annotations/labels to it.

Which should be useful to replicate theses secrets automatically to another(s) cluster(s) using systems like "kubed/config-syncer", which check for an specific annotations on the secrets/configmaps to be replicate.

Describe the solution you'd like

private key creation/rotation should accept a list of annotations/labels from the controller configuration.

--privatekey-annotations 'kubed.appscode.com/sync: ""'
--privatekey-labels 'app.kubernetes.io/instance=production-cluster' --privatekey-labels 'app.kubernetes.io/part-of=sysadmin'

Additional context Replicate secrets between clusters using [kubed/config-syncer](https://github.com/kubeops/config-syncer)

Note: Not sure if someone have this kind of tasks (replicate the private key between cluster) covered using another solution ?