Move NPM package files out of /lib ; affects [resharper nuget myget dub chocolatey github] (#2300)

* move gh-badges files out of /lib

As far as possible, this is just moving files
around and updating paths however there are 2
functional changes in this commit:
- remove use of lib/register-chai-plugins.spec
  in badge-cli.spec.js
- remove use of starRating()
  in text-measurer.spec.js

* update service tests that use colorscheme.json

* split package.json in two

* clean up import

* don't hard-code path

* start a changelog

* put a license file in the package dir

* re-organise documentation 

* don't pack test files

* remove favicon from Makefile

* give package its own test command

* link the docs better in README