Properly collect NTP metrics from hosts

GitLab Infrastructure Service - incident.io
2026-04-02T10:11:14Z

_This ticket was created from_ [_INC-8646_](https://app.incident.io/gitlab/incidents/8646) _using_ [_incident.io_](https://app.incident.io) 🔥

We have node_exporter configured to collect NTP metrics, however, no metrics is emitted from our VMs such as Gitaly. Moreover, the collector itself has been [deprecated](https://github.com/prometheus/node_exporter/commit/c8705ec4b296aaec20ea5fc4f130b099ab61012f) by the exporter and is expected to be removed in a major version, so we need to find an alternative or drop it from our config altogether.