Update with_items loops to use new-ish "loop" keyword

Ansible 2.4 and 2.5 are moving away from specialized loop functions
and the old syntax will eventually be deprecated and removed. I did
not change the with_fileglob loops because I'm not sure about their
syntax yet.

See: https://docs.ansible.com/ansible/latest/user_guide/playbooks_loops.html

roles/common/tasks/firewall_Debian.yml

@@ -2,7 +2,7 @@
 - name: Install firewalld and deps
   when: ansible_distribution_major_version is version_compare('8', '>=')
   apt: pkg={{ item }} state=present
-  with_items:
+  loop:
     - firewalld
     - tidy
   tags: packages