Add host exclusion and improve UFW task reliability

Add `excluded` host group and skip offline hosts
Fix UFW service initialization command for Alpine Linux

roles/ufw/tasks/main.yml

@@ -17,7 +17,7 @@
 
 - name: Add UFW to default runlevel (Alpine)
   ansible.builtin.command:
-    cmd: rc-update add ufw default
+    cmd: /sbin/rc-update add ufw default
   register: ufw_rc_update_result
   changed_when: >- # " >- : transform multiple lines into one line"
     'already' not in ufw_rc_update_result.stdout