US102 As a developer, I want to customise backup schedules and retention policies based on my specific needs

Description:

As a developer, I want to customize backup schedules and retention durations, so that I can align them with the requirements of my application, business continuity plans, and storage constraints.

Linked Requirements & Use Cases:

• Requirements ID - BUSINESS-REQ-10, BUSINESS-REQ-11, BUSINESS-REQ-74, BUSINESS-REQ-99
• Use Case 0016 - UC16

Current Definition of Done

• Backup scheduling can be configured by the developer.
• The retention policy can be configured (e.g., 7 days, 30 days, custom date).
• Backups exceeding the specified time period are automatically deleted or archived.
• How to configure these settings in a Docker/CI/CD environment is documented.
• Tests verify that both scheduling and deletion work correctly.

Acceptance Criterias

• Full backups (including files, images, and themes) are created automatically at scheduled intervals. (#292)
• Backup cron schedule can be set per project or environment
• Developer can define how many backups to retain or how long (e.g., in days)
• Old backups are deleted automatically without affecting system integrity
• System generates logs and alerts for backup and cleanup operations