Plugins: Migrate CloudWatch to backend plugin SDK (#31149)

* first pass

* add instance manager

* fix tests

* remove dead code

* unexport fields

* cleanup

* remove ds instance from executor

* cleanup

* inline im

* remove old func

* get error working

* unexport field

* let fe do its magic

* fix channel name

* revert some tsdb changes

* fix annotations

* cleanup

pkg/tsdb/cloudwatch/test_utils.go

@@ -15,37 +15,9 @@ import (
 	"github.com/aws/aws-sdk-go/service/resourcegroupstaggingapi"
 	"github.com/aws/aws-sdk-go/service/resourcegroupstaggingapi/resourcegroupstaggingapiiface"
 	"github.com/grafana/grafana-aws-sdk/pkg/awsds"
-	"github.com/grafana/grafana/pkg/components/securejsondata"
-	"github.com/grafana/grafana/pkg/components/simplejson"
-	"github.com/grafana/grafana/pkg/models"
 	"github.com/grafana/grafana/pkg/setting"
 )
 
-type fakeDataSourceCfg struct {
-	assumeRoleARN string
-	externalID    string
-}
-
-func fakeDataSource(cfgs ...fakeDataSourceCfg) *models.DataSource {
-	jsonData := simplejson.New()
-	jsonData.Set("defaultRegion", defaultRegion)
-	jsonData.Set("authType", "default")
-	for _, cfg := range cfgs {
-		if cfg.assumeRoleARN != "" {
-			jsonData.Set("assumeRoleArn", cfg.assumeRoleARN)
-		}
-		if cfg.externalID != "" {
-			jsonData.Set("externalId", cfg.externalID)
-		}
-	}
-	return &models.DataSource{
-		Id:             1,
-		Database:       "default",
-		JsonData:       jsonData,
-		SecureJsonData: securejsondata.SecureJsonData{},
-	}
-}
-
 type FakeCWLogsClient struct {
 	cloudwatchlogsiface.CloudWatchLogsAPI
 	logGroups      cloudwatchlogs.DescribeLogGroupsOutput