[FEATURE] Node type label in the opensearch metrics

[ragu2003]

Is your feature request related to a problem?
Currently it returns metrics for all the nodes. Only way to distinguish them is by node name.

What solution would you like?
Currently we can do:
opensearch_os_cpu_percent{cluster="$cluster", node=~"data-node-0"}
It will be great if we can also do something like this:
opensearch_os_cpu_percent{cluster="$cluster", nodetype=~"data"}

What alternatives have you considered?
In our grafana dashboard we differentiate them by regex of node name but it is not reliable. As anyone can name their nodes differently for different node types

[lukas-vlcek]

Sounds like useful feature.