Add repo foundation: proxmox/lxc/vms groups, ansible.cfg, collections, lint configs

- inventory: add proxmox host, lxc and vms groups, critical_services per host
- retarget bootstrap and time-region to ubuntu:rocky so the Proxmox host is untouched
- add ansible.cfg, collections/requirements.yml, .gitignore, .yamllint, .ansible-lint
- remove stale root new_lxc.yml duplicate and the Nextcloud upgrade playbook

Claude-Session: https://claude.ai/code/session_01JEczyvRjfakkiDNkbZA7PR

playbooks/health_check.yml

@@ -59,4 +59,4 @@
       ansible.builtin.debug:
         msg: "WARNING: {{ item.split()[-1] }} usage on {{ item.split()[0] }} of {{ inventory_hostname }}"
       loop: "{{ disk_usage.stdout_lines }}"
-      when: (item.split()[-1] | replace('%','') | int) > 85
+      when: (item.split()[-1] | replace('%', '') | int) > 85