reboot(role): intro. reboot role, which handles local conns. gracefully

Also use this role instead of plain ansible.builtin.reboot.
This is in preparation for using ansible_pull as we don't want to have
ansible.builtin.reboot fail local playbook runs.

roles/apt_update_and_upgrade/handlers/main.yaml

@@ -1,3 +1,5 @@
 - name: reboot the system
-  become: true
-  ansible.builtin.reboot:
+  ansible.builtin.include_tasks: "../../reboot/tasks/main.yaml"
+  vars:
+    # Simply don't reboot on local connections and rely on proper handling of /var/run/reboot-required.
+    reboot__local_handling: ignore