Provide simple instructions/script to run nix build distributed on lab machines

[domenkozar]

http://nixos.org/nix/manual/#chap-distributed-builds

idea: just build a script with snabblab and add it to snabblab jobset

[domenkozar]

If something is built on eiger, it's distributed over the build machines.

This is not something I've proved with hard facts yet, but I've observed that Hydra and local invocations don't use the same counters so for example build1 is now building two kernels while the rest of 3 machines are idle.

[domenkozar]

This is almost what's needed: NixOS/nixpkgs#16263