Fix issues found by ansible-lint

Using ansible.builtin.service in place of service and
adding handlers for roles/load_balancer/tasks/main.yml

Author: GavinHeff

roles/load_balancer/tasks/main.yml

@@ -4,10 +4,10 @@
     src: nginx.conf.j2
     dest: /etc/nginx/conf.d/sample-appliance.conf
     mode: '0644'
-  register: nginx_conf
+  notify: Restart Nginx
 
-- name: Restart Nginx if required
-  service:
-    name: nginx
-    state: restarted
-  when: nginx_conf is changed
+  handlers:
+    - name: Restart Nginx
+      ansible.builtin.service:
+        name: nginx
+        state: restarted