Add monitoring and alerting

[science]

Summary

Add basic monitoring and alerting for the DefectDojo infrastructure.

Requirements

• Health check endpoint monitoring (is DefectDojo responding?)
• Disk space alerts (Docker can fill up disk)
• Backup success/failure notifications
• SSL certificate expiration alerts

Options to Consider

1. AWS CloudWatch - Native to AWS, can alert on EC2 metrics
2. UptimeRobot/Pingdom - Simple HTTP monitoring
3. GitHub Actions scheduled workflow - Run health checks periodically

Minimum Viable

• Health check that pings /api/v2/ every 5 minutes
• Slack/email notification if down for >10 minutes
• Weekly backup success confirmation