Add IPv4 vs IPv6 Metric to xmidt_talaria_hardware_model

[schmidtw]

It would be very helpful if we can see the type of IP address (IPv4 vs IPv6) used by xmidt_talaria_hardware_model.

Ideally we'd add a label ip_version of 4 or 6 to the xmidt_talaria_hardware_model metric.

[joe94]

Since there's a high chance we will be adding various custom metrics to our servers. We need to research whether implementing a common pattern / library might make the most sense as a solution (as opposed to simply adding scattered metrics boilerplate code). "Fun independent project" - @johnabass