Implementing creation, listing, and deletion of firewall rules for QEMU

[PascalKu]

This pull request introduces new functionality for managing firewall rules within the qemu/{vmid}/firewall context. The implemented features include:

• Creation of firewall rules for a specific virtual machine (vmid).
• Listing of all existing firewall rules associated with the specified virtual machine.
• Deletion of firewall rules based on a given position within the rule list.

[PascalKu]

please review :)