group: Use FQCN for ansible.builtin

Use Fully Qualified Collection Name (FQCN) for ansible builtins. This is
ansible.builtin.set_fact instead of set_fact for example and aplies for
all actions that are part of ansible.builtin.

All the replaced ansible.builtins:
  assert, command, copy, debug, fail, fetch, file, import_playbook,
  import_tasks, include_role, include_tasks, include_vars, package,
  set_fact, shell, slurp, stat, systemd

tests/group/test_group.yml

@@ -6,12 +6,12 @@
 
   tasks:
   # setup
-  - include_tasks: ../env_freeipa_facts.yml
+  - ansible.builtin.include_tasks: ../env_freeipa_facts.yml
 
   # GET FQDN_AT_DOMAIN
 
   - name: Get fqdn_at_domain
-    set_fact:
+    ansible.builtin.set_fact:
       fqdn_at_domain: "{{ ansible_facts['fqdn'] + '@' + ipaserver_realm }}"
 
   # CLEANUP TEST ITEMS