Update to latest Aerleon version, update available generators

[loulecrivain]

Depends on #308, will be rebased once #308 is merged

What's Changed

• Upgrade to latest Aerleon version 1.9.x (not yet published, next release window is 18-06-2025)
• Change in minimal Python version constraints for Aerleon
• Add Proxmox Firewall generator
• Add Fortigate Firewall generator

To Do

• Explanation of Change(s)
• Added change log fragment(s) (for more information see the documentation)
• Attached Screenshots, Payload Example
• Unit, Integration Tests
• Documentation Updates (when adding/changing features)
• Outline Remaining Work, Constraints from Design