Increase query lookback delta

Prometheus will regard metrics collected over this perioid as stale as
such they won't show up in grafana.

Author: jovial

etc/kayobe/kolla/globals.yml

@@ -26,7 +26,7 @@ kolla_image_tags:
 # Monitoring and alerting related settings
 
 opensearch_heap_size: 8g
-prometheus_cmdline_extras: "--storage.tsdb.retention.time=30d"
+prometheus_cmdline_extras: "--storage.tsdb.retention.time=30d --query.lookback-delta=15m"
 
 # Additional command line flags for node exporter to enable texfile collector for disk metrics and create textfile docker volume
 prometheus_node_exporter_extra_volumes: