restore-backup.yml playbook does not support restoring a backup from staging

[SilasPeters]

The create-backup.yml playbook mentions (and seems to support) to create a backup to a dediacted staging S3 bucket (which exists). However, the restore-backup.yml playbook does not support restoring the staging backup, and instead mentions that this script can be used to test the integrity of 'the backup' - whilst restoring production data to staging is risky.

Restoring a staging backup is essential to test backups works.