Add RHEL Bare Metal Recovery (ReaR) script for Generic Application AgentFeature/rhel bmr rear

[t-oda-jp]

🚀 Summary

Add RHEL Bare Metal Recovery (ReaR) backup script for PPDM Generic Application Agent (PaaS type).
The script dynamically configures ReaR to store a bootable ISO and backup archive directly to the PPDM-managed BoostFS target directory.

🛠️ Type of Change

• Bug fix
• New feature
• Documentation update
• Refactoring
• Other (please describe):

✅ Checklist

• My code follows the project style guidelines
• I have performed a self-review of my code
• Documentation has been updated as needed
• I have included or updated tests as appropriate
• I have specified the PowerProtect Data Manager (PPDM) version(s) used to validate/test this change
  • Tested PPDM version(s): 19.22`

🧪 How to Test

1. Configure a PPDM Generic Application Agent asset (PaaS type) on a RHEL host
2. Assign rhel_bmr_rear_backup.sh as the backup script
3. Run a FULL backup job from PPDM
4. Verify that .iso and backup.tar.gz are created in DD_TARGET_ASSET_BASE_PATH