* cleanup cloudwatch.go
* streamline interface naming
* use utility func
* rename test utils file
* move util function to where they are used
* move dtos to models
* split integration tests from the rest
* Update pkg/tsdb/cloudwatch/cloudwatch.go
Co-authored-by: Isabella Siu <Isabella.siu@grafana.com>
* refactor error codes aggregation
* move error messages to models
Co-authored-by: Isabella Siu <Isabella.siu@grafana.com>
