Override container insights metrics log group

Context: I'm running cloudwatch agent for container insights on EKS.

Right now, container insights metrics are stored on the following Log Group from Cloudwatch:

* /aws/containerinsights/{{eks_cluster_name}}/performance

For pure cosmetical reasons, I would like to change this default to something else.

I found [on the official documentation](https://docs.aws.amazon.com/AmazonCloudWatch/latest/monitoring/CloudWatch-Agent-Configuration-File-Details.html) how to customize it for log directives.that deals with logs_collected

```
log_group_name – Optional. Specifies what to use as the log group name in CloudWatch Logs. As part of the name, you can use {instance_id}, {hostname}, {local_hostname}, and {ip_address} as variables within the name. {hostname} retrieves the hostname from the EC2 metadata, and {local_hostname} uses the hostname from the network configuration file.
```

Unfortunately, that directive does not seem to work with metrics, nor I could find any examples of it anywhere else.

Any hints on how (and if) it's done?

Start with the CloudWatch Agent configuration details linked in the issue, especially the log_group_name directive, and compare its documented behavior with the Container Insights metrics configuration for EKS. Determine whether metrics log groups support an override; done means identifying a supported configuration path or documenting that the default cannot be changed.

Written by the indexing model from the issue text.