Include mount_point in Kubernetes volume metricset

[eedugon]

Describe the enhancement:

This enhancement is slightly related to #39524, as the goal is to improve the monitoring of volumes.

Ideally it would be great to include the mount_point of kubernetes volumes, as all the volumes we collect are belonging to pods, and the pods are mounting the volumes in certain locations.

Anyway this request might be challenging, as internally the mount point is not part of the volume definition on the pod, it's included in the volumeMounts section. Hence I don't know how feasible this would be.

Including the mount points would give much better visibility to users monitoring their Kubernetes infrastructure.

Describe a specific use case for the enhancement or feature:

Kubernetes volumes and pods monitoring.

[elasticmachine]

Pinging @elastic/obs-ds-hosted-services (Team:obs-ds-hosted-services)

[botelastic]

Hi!
We just realized that we haven't looked into this issue in a while. We're sorry!

We're labeling this issue as Stale to make it hit our filters and make sure we get back to it as soon as possible. In the meantime, it'd be extremely helpful if you could take a look at it as well and confirm its relevance. A simple comment with a nice emoji will be enough :+1.
Thank you for your contribution!