Improve description for parameter delete_file_age in the scheduler_rotate_log job

Current Situation

Examples are missing that describe available units for the value of the parameter delete_file_age.

Desired Behavior

The available units are explained as for the file_age parameter:

• 14d – 14 days
• 2w – 2 weeks
• 24h – 24 hours
• 60m – 60 minutes
• 2s – 2 seconds
• 02:03:04 – 2 hours, 3 minutes, 4 seconds
• 72:00:00 – 3 days