feat ✨: Add Fail2ban integration with Proxmox Firewall

This commit adds Fail2ban settings to `defaults/main.yml`, a new task to restart the fail2ban service, and a task file for deploying Fail2Ban integrated with Proxmox Firewall. The new tasks include checks, validations, and configuration to enhance security by blocking malicious IP addresses.

defaults/main.yml

@@ -47,3 +47,15 @@ journald_runtime_max_use: "100M"
 vm_dirty_ratio: 15
 vm_dirty_background_ratio: 5
 vm_swappiness: "{{ proxmox_swapiness }}"
+
+# Fail2ban settings
+f2b_bantime: 1800             # 30 minutes
+f2b_findtime: 600
+f2b_maxretry: 5
+f2b_recidive_bantime: 86400    # 24 hours
+f2b_recidive_findtime: 86400   # 24 hours
+f2b_recidive_maxretry: 3
+f2b_ipset_name: f2b-blacklist
+f2b_bantime_increment: true
+f2b_bantime_factor: 2
+f2b_bantime_max: 86400