Add Pi-hole and Traefik LXC containers

- LXC 103 (pihole): Debian 12, 10.10.1.2, Pi-hole v6 with local DNS for
  gitea/grafana/traefik/pihole.homelab, Proxmox dnsmasq updated to use
  Pi-hole upstream
- LXC 104 (traefik): Debian 12, 10.10.1.3, Traefik v3 routing
  gitea.homelab → 10.10.1.125:3000, grafana.homelab → 10.10.1.137:3000
- DNAT rules on vmbr0 forwarding :80/:443 to Traefik, persisted in
  /etc/network/interfaces
- Ansible roles: pihole, traefik; playbooks: pihole.yml, traefik.yml
- site.yml excludes Debian containers from Arch-specific common role

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

ansible/roles/pihole/templates/setupVars.conf.j2

@@ -0,0 +1,15 @@
+PIHOLE_INTERFACE={{ pihole_interface }}
+PIHOLE_DNS_1={{ pihole_dns_upstream1 }}
+PIHOLE_DNS_2={{ pihole_dns_upstream2 }}
+QUERY_LOGGING=true
+INSTALL_WEB_SERVER=true
+INSTALL_WEB_INTERFACE=true
+LIGHTTPD_ENABLED=true
+CACHE_SIZE=10000
+DNS_FQDN_REQUIRED=false
+DNS_BOGUS_PRIV=true
+DNSMASQ_LISTENING=local
+WEBPASSWORD=
+BLOCKING_ENABLED=true
+PIHOLE_DOMAIN={{ pihole_local_domain }}
+IPV4_ADDRESS=10.10.1.2/24