Add Backup Support for Backblaze S3

Currently the backup server requires another linux server with rsync to handle the backups. and only Amazon S3 is supported.

But there are lot of other storage providers like Wasabi, Backblaze, Hetzner, Contabo etc. There is no option to connect and handle backups to these places. 

Please integrate a system for the same. Backblaze preferred as unlike Wasabi they have public buckets from start and doesn't take 2 months to reply to email

Thank you.