Cinder V3: Support a backup record export and import #1892
Description
Export a backup: https://docs.openstack.org/api-ref/block-storage/v3/?expanded=export-a-backup-detail#export-a-backup
https://github.com/openstack/cinder/blob/c29285e7dcda7f5300c5a3375294dfa4aeb56430/cinder/api/contrib/backups.py#L239..L253
Import a backup: https://docs.openstack.org/api-ref/block-storage/v3/?expanded=import-a-backup-detail#import-a-backup
https://github.com/openstack/cinder/blob/c29285e7dcda7f5300c5a3375294dfa4aeb56430/cinder/api/contrib/backups.py#L257..L280