prometheus-node-exporter: 0.15.2 -> 0.16.0

[Mrmaxmeier]

Motivation for this change

https://github.com/prometheus/node_exporter/blob/master/CHANGELOG.md#0160--2018-05-15

Things done

• Tested using sandboxing (nix.useSandbox on NixOS, or option sandbox in nix.conf on non-NixOS)
• Built on platform(s)
  • NixOS
  • macOS
  • other Linux distributions
• Tested via one or more NixOS test(s) if existing and applicable for the change (look inside nixos/tests)
• Tested compilation of all pkgs that depend on this change using nix-shell -p nox --run "nox-review wip"
• Tested execution of all binary files (usually in ./result/bin/)
• Fits CONTRIBUTING.md.

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Note: This release contains a bunch of user-facing breaking changes as many metrics have been renamed.