hosts: Decommission mtrcs0.p.b

The Metrics Pi has bit the dust.  The NVMe disk has never been
particularly reliable, but now it's gotten to the point where it's a
real issue.  The Pi needs rebooted at least once a day.

I've moved the Victoria Metrics/Grafana ecosystem to Kubernetes.

hosts

@@ -26,7 +26,6 @@ burp1.pyrocufflink.blue
 [certbot]
 
 [collectd]
-mtrcs0.pyrocufflink.blue
 
 [collectd:children]
 pyrocufflink
@@ -60,7 +59,6 @@ file0.pyrocufflink.blue
 git0.pyrocufflink.blue
 
 [grafana]
-mtrcs0.pyrocufflink.blue
 
 [graylog]
 logs0.pyrocufflink.blue
@@ -91,7 +89,6 @@ k8s-controller
 k8s-node
 
 [metricspi]
-mtrcs0.pyrocufflink.blue
 
 [minio:children]
 burp-server