Audit of copenhagen-a found several running services not captured in
host_vars: cloudflared, node_exporter (systemd), and MariaDB. Also
found postgresql and redis running with no active consumers.
Updated host_vars to list all services and added undocumented_services
for the potentially unused ones. Updated docs with cloudflare tunnel,
monitoring, and notes about stale Docker images to clean up.
Closes PESO-100
