feat: manage encrypted buckets

[St4NNi]

Description

The portal can now manage encrypted buckets on Aruna nodes. Group admins enable encryption and choose the key mode, cipher and block keys. Key holders unlock, extend and lock buckets with their own key, manage holders, rotate keys and read the audit trail. Locked buckets are shown as locked when their content is read.

Changes

• Encryption tab on the bucket page with status, settings, unlock, extend and lock.
• Holder list with grants, removals and recovery confirmation, and the user's own key copies.
• Key rotation and the bucket audit trail.
• Unlock sends the 32-byte bucket key as a binary request body.
• Settings changes and rotation send the bucket's storage generation.
• Plain wording for every refusal code of the encryption routes.
• Notifications for bucket_locked_by_restart and bucket_recovery_degraded, linking to the bucket's encryption tab on its node.
• Locked-content handling for reads that answer x-aruna-bucket-locked: true.