Suggestion: Add an ephemeral_storage_container_volume_limit Metric

[NoamVH]

The current metrics that I see are available in the exporter related to containers are:

ephemeral_storage_container_limit_percentage
ephemeral_storage_container_volume_limit_percentage
ephemeral_storage_container_volume_usage
ephemeral_storage_pod_usage

I think an ephemeral_storage_container_volume_limit metric would be a great addition, if there's a limit percentage metric already, I believe this should be possible, I'm currently extracting this value by dividing ephemeral_storage_pod_usage by 0.01 * max(ephemeral_storage_container_limit_percentage), but it's uneeded computation, it'd be better to just have the limit as a metric by itself that can be used in different ways.