Volume Snapshot Data Movement - DataDownload controller state machine

[Lyndon-Li]

Implement the DataDownload controller state machine, includes:

• Register DataDownload controller to controller manager
• Flows DataDownload CRs appropriately among different phases - new, accepted, preparing, prepared, in-progress, completed, failed
• Implement the DataDownload object lock for accept phase

[github-actions]

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[Lyndon-Li]

Fixed by #6337 #6436