Refactor backup controller with kubebuilder

[blackpiglet]

Describe the problem/challenge you have
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A sub task of epic #2597 to refactor backup controller with kubebuilder.

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Anything else you would like to add:
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Environment:

• Velero version (use velero version):
• Kubernetes version (use kubectl version):
• Kubernetes installer & version:
• Cloud provider or hardware configuration:
• OS (e.g. from /etc/os-release):

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