common: sparkle some {{ansible_managed}} in the templates

Signed-off-by: Mattia Rizzolo <mattia@debian.org>

roles/common/templates/firewall/firewall.service

+#
+# {{ ansible_managed }}
+#
+
 [Unit]
 Description=Firewall initialization script
 After=network.target

roles/common/templates/firewall/firewall.sh

 #!/bin/bash
+#
+# {{ ansible_managed }}
+#
 
 # Check if ip6tables is supported by the machine
 if which ip6tables >/dev/null 2>&1 && /sbin/ip6tables -L >/dev/null 2>&1; then

roles/common/templates/ssh/sshd_config

+#
+# {{ ansible_managed }}
+#
+
 Port 22
 ListenAddress ::
 ListenAddress 0.0.0.0

roles/common/templates/users/sudoers-passwordless-sudo

+#
+# {{ ansible_managed }}
+#
 # Allow the passwordless-sudo group to use sudo without password
 %passwordless-sudo ALL=(ALL:ALL) NOPASSWD:ALL