Add backup and restore

[0x3639]

This PR adds the ability to backup and restore node data locally. In addition, a user can select to restore from a remote backup at Digital Ocean. A user would need to know the URL of a backup. It cannot be found publicly.

[georgezgeorgez]

So the way I would approach this would be to use standard APIs such as s3 and to offer flexibility
For example, if there is a restore command then it could take a path argument. That path could be a local path like /path/to/backup/ or a s3 path like s3://my-backup-bucket/path/to/backup. Many cloud storage providers offer object storage with an s3 compatible interface. A few more config flags may be needed for s3 endpoint, regions, etc. As HC1, we could offer a default public backup file. But this way users can upload their own backups and point to them as well.