netlink: add node_network_altnames_info metric

[ajaggapa]

Creating a mapping for altnames and device names with new node_network_altnames_info

This will be used to fetch any other metrics that have only device name label but not altname.

[SuperQ]

Maybe #3540 is a better option.

[ajaggapa]

Maybe #3540 is a better option.

@SuperQ
We have both approaches, the problem i find with #3540 is that we need to use regex to match altname instead of exact match. WDYT ?