ansible_pull(role): introduce ansible_pull role

Introduce ansible_pull role for setting up automatic ansible_pull runs.
Also add accompanying host group and playbook play.

playbooks/deploy.yaml

@@ -78,5 +78,10 @@
       ansible.builtin.include_role:
         name: grafana.grafana.alloy
 
+- name: Ensure ansible_pull deployment on ansible_pull_hosts
+  hosts: ansible_pull_hosts
+  roles:
+    - ansible_pull
+
 - name: Run ensure_eh22_styleguide_dir Playbook
   ansible.builtin.import_playbook: ensure_eh22_styleguide_dir.yaml