Easily configure arguments of node exporter

[Alek Hrycaiko]

What is missing?

An easy way of managing the addition of collectors (e.g. ethtool) on node exporter.

Why do we need it?

Having certain additional collectors is possible with node exporter but a simple config currently doesn't exist. The current args are housed in a local scoped to the function, which appears like it'd make additions difficult.

Environment

• kube-prometheus version:

  407142589d5b38663e70f80c6c3b493e5b5e6578

Anything else we need to know?:

Ideally a config would be nice, but alternatively some example documentation on how to approach this would be helpful for consumers.