CloudWatch: Add macro for resolving period in SEARCH expressions (#60435)

* interpolate macro in the backend

* refactor logger in cloudwatch query

* revert added metrics

* add docs

* apply pr feedback

* fix broken test

* fix spelling

docs/sources/datasources/aws-cloudwatch/query-editor/index.md

@@ -92,6 +92,10 @@ For example, to apply arithmetic operations to a metric, apply a unique string i
 
 > **Note:** If you use the expression field to reference another query, like `queryA * 2`, you can't create an alert rule based on that query.
 
+##### Period macro
+
+If you're using a CloudWatch [`SEARCH`](https://docs.aws.amazon.com/AmazonCloudWatch/latest/monitoring/search-expression-syntax.html) expression, you may want to use the `$__period_auto` macro rather than specifying a period explicitly. The `$__period_auto` macro will resolve to a [CloudWatch period](https://docs.aws.amazon.com/AmazonCloudWatch/latest/APIReference/API_GetMetricData.html) that is suitable for the chosen time range.
+
 #### Deep-link Grafana panels to the CloudWatch console
 
 {{< figure src="/static/img/docs/v65/cloudwatch-deep-linking.png" max-width="500px" class="docs-image--right" caption="CloudWatch deep linking" >}}