br: add local encryption to log/stream backup #55834
Description
Enhancement
Right now we have local encryption for snapshot backup by passing into a plaintext data key from user.
This feature adds the same plaintext data key for log backup, in addition to that, it allows user to configure a master key based key encryption (kms or on local disk) for log backup. We might add the same support for snapshot backup in the same change if time allows.
With this feature the end to end encryption for backup & restore lifecycle will be complete.
Related change: