alerting is handled by grafana, not alertmanager. removed the
stale reverse proxy block from caddyfile template and updated
caddy + prometheus docs to reflect grafana-only alerting.
Remove webdav.pez.sh DNS record (WebDAV replaced by Nextcloud AIO on cloud.pez.sh)
Remove alertmanager.pez.sh DNS record and Caddyfile block (Alertmanager not running on london-a)
Remove status-https HTTPS record pointing to old statuspage.io (status.pez.sh is self-hosted on helsinki-a)
Remove commented-out WebDAV block from Caddyfile
Remove empty section headers for decommissioned hosts (london-c, copenhagen-b, copenhagen-c)
Closes PESO-102
Alertmanager reverse_proxy was pointing to :3000 (Grafana) instead of
:9093 (Alertmanager). Copy-paste artifact. Fixed in both the Caddyfile
and the template.
