Better Backups

Initial release of Better Backups.

• Added manual backups with /backup start.
• Added backup listing with /backup list.
• Added world restore with /backup restore <backup>.
• Added scheduled backups with configurable intervals.
• Added automatic cleanup with a configurable backup limit.
• Added /backup status and /backup config.
• Added server-side restore flow with stopAfterRestore.
• Backups are named with local timestamps and timezone offsets.