Add more time options to dietpi-backup

[Joulinar]

Or simply create own individual cron jobs

0 0 * * * dietpi-backup 1 /mnt/backup/daily
0 1 * * 1 dietpi-backup 1 /mnt/backup/weekly
0 2 1 * * dietpi-backup 1 /mnt/backup/monthly
0 3 1 1 * dietpi-backup 1 /mnt/backup/yearly