This PR upgrades the kubebuilder version used by the secureCodeBox Operator to v3.
This also includes the migration of the CRD's from apiextensions.k8s.io/v1beta1 to apiextensions.k8s.io/v1

Upgrade notes

• The CRD's are now using apiextensions.k8s.io/v1 which requries at least Kubernetes Version 1.16 or higher.
• The Operator now uses the new kubebuilder v3 command line flag for enabling leader election and setting the metrics port. If you are using the official secureCodeBox Helm Charts for your Deployment this has been updated automatically. If you are using a custom deployment you have to change the --enable-leader-election flag to --leader-elect and --metrics-addr to --metrics-bind-address. For more context see: https://book.kubebuilder.io/migration/v2vsv3.html#tldr-of-the-new-gov3-plugin