EKS detector using method that relies on AWS CloudWatch exporter presence which is not really common

[IgorEulalio]

Description

EKS detector relies on the presence of a configmap that is not deployed in EKS environment by default, it is only deployed when using the cloudwatch exporter which is really not used much:
https://docs.aws.amazon.com/AmazonCloudWatch/latest/monitoring/Container-Insights-setup-metrics.html
https://github.com/open-telemetry/opentelemetry-go-contrib/blob/main/detectors/aws/eks/detector.go#L162

With the current approach, only clusters with this installed will get the clusterName populated, a better approach would be to rely on EC2 Metadata + EKS Worker node labels.

There's a issue open on AWS containers roadmap asking for a more straightforward way to collect this information but this is the unique approach that current works consistently across EKS deployments:
aws/containers-roadmap#686

Environment

• OS: an
• Architecture: any
• Go Version: any
• eks version: any

Steps To Reproduce

1. Deploy application with detector EKS in any fresh EKS cluster
2. Detect will return empty clusterName

Expected behavior

For any EKS environment we should be able to perform the resource collection and inform back the cluster name.

[dmathieu]

cc @pyohannes as code owner.

[IgorEulalio]

@pyohannes @dmathieu I have a PR open implementing above mentioned behavior.

It relies on AWS EC2 metadata + IAM role associated to EKS worker node which by default need access to list labels:
IgorEulalio#1

Let me know if that's something that makes sense and I'll be glad to open a PR to sync the fork.