Convert CloudWatch to use dataframes (#26702)

* CloudWatch: Convert metrics queries to return data frames

Signed-off-by: Arve Knudsen <arve.knudsen@gmail.com>

pkg/tsdb/cloudwatch/get_metric_data_executor_test.go

@@ -7,6 +7,7 @@ import (
 	"github.com/aws/aws-sdk-go/aws"
 	"github.com/aws/aws-sdk-go/aws/request"
 	"github.com/aws/aws-sdk-go/service/cloudwatch"
+	"github.com/aws/aws-sdk-go/service/cloudwatch/cloudwatchiface"
 	"github.com/stretchr/testify/assert"
 	"github.com/stretchr/testify/require"
 )
@@ -14,6 +15,7 @@ import (
 var counter = 1
 
 type cloudWatchFakeClient struct {
+	cloudwatchiface.CloudWatchAPI
 }
 
 func (client *cloudWatchFakeClient) GetMetricDataWithContext(ctx aws.Context, input *cloudwatch.GetMetricDataInput, opts ...request.Option) (*cloudwatch.GetMetricDataOutput, error) {