Datasources: Use getDefaultQuery in annotations editors (#61870)

+ Add Cloudwatch default annotation

packages/grafana-data/src/types/annotations.ts

@@ -113,4 +113,9 @@ export interface AnnotationSupport<TQuery extends DataQuery = DataQuery, TAnno =
    * Specify a custom QueryEditor for the annotation page.  If not specified, the standard one will be used
    */
   QueryEditor?: ComponentType<AnnotationQueryEditorProps<TQuery>>;
+
+  /**
+   * Define this method if you want to pre-populate the editor with a default query
+   */
+  getDefaultQuery?(): Partial<TQuery>;
 }