Enable Goldpinger_Node_Unhealthy alert on workload clusters

Goldpinger is deployed and scraping metrics on workload clusters, but the Goldpinger_Node_Unhealthy PrometheusRule is not created there. No alert fires when a workload cluster node reports a connectivity outage.

In the sylva-prometheus-rules chart, goldpinger.yaml lives under alert-rules/management-cluster/.

Move goldpinger.yaml (or add it) into alert-rules/allclusters/, I am not sure what is the exact way to make it work on both mgmt and workload clusters.