`npm root -g` and `npm bin -g` should be sped up

Even on the latest npm versions, `npm root -g` and `npm bin -g` are really slow, surely because they load all sorts of files on program load.  I would like to use them as part of shell scripts but they are really slow and expensive commands.

Solution - create an npm entry point that doesn't load everything, and for certain commands don't load all the code.