Add a telegraf role (applied to the resolvers) that runs unbound-control
via the inputs.unbound plugin and exposes the stats as a Prometheus
/metrics endpoint on :9273, firewalled to the 204.110.188.0/22 scrape
network. Imports the InfluxData signing key (influxdata-archive.key; the
_compat key expired 2026-01-17) so dnf can validate the package.
- prom.w5isp.com: scrape job "unbound" for resolver1/2:9273
- grafana: "Unbound Resolvers" dashboard (queries, cache hit ratio,
rcodes, query types, recursion time, request list, cache memory)
- resolvers: disable unused shm-enable to silence the startup warning
