Add metrics retention documentation

documentation/monitoring.md

@@ -158,7 +158,9 @@ Unfortunately we can't alert which kubernetes service is using aa high number of
 
 [Troubleshoot SNAT port exhaustion on Azure Kubernetes Service nodes](https://learn.microsoft.com/en-us/troubleshoot/azure/azure-kubernetes/connectivity/snat-port-exhaustion?tabs=for-a-linux-pod)
 
-## Metrics Retention
+## Querying metrics
+
+### Metrics Retention
 
 Metrics retention is based on sampling
 - Raw data(actual data captured) is retained for 30 days. This is data as it is captured by prometheus.
@@ -168,7 +170,6 @@ Metrics retention is based on sampling
 More information on down sampling is available on this [link](https://thanos.io/v0.8/components/compact/#downsampling-resolution-and-retention)
 
 Down sample allows for reduced storage costs as all the raw data does not need to stored for longer duration charting.
-## Querying metrics
 
 ### Thanos UI
 Metrics can be queried/charted by using thanos UI. While charting metrics in thanos the following should be noted