standalone-shared: install iptables on debian 11

Keep using iptables for compatibility with our scripts using iptables.

playbook/roles/standalone-shared/tasks/main.yml

@@ -26,6 +26,14 @@
       minute=*/5
       job="/usr/bin/slapos console '/tmp/playbook-request-frontend-{{ playbook_name }}' > /dev/null 2>&1"
 
+  # Debian 11 uses nftables instead of iptables, we replace nftables by iptables for our scripts using iptables
+  - name: Remove nftables
+    apt: name=nftables state=absent
+    when: ansible_distribution == "Debian" and ansible_distribution_major_version == "11"
+  - name: Install iptables-persistent (for iptables and iptables --save)
+    apt: name=iptables-persistent state=present
+    when: ansible_distribution == "Debian" and ansible_distribution_major_version == "11"
+
   - name: Create firewall script
     template: src={{ firewall_setup_template }} dest=/tmp/playbook-firewall-setup-{{ playbook_name }} mode=0700