VERSIONING: Show Semver Tag, Build No. or Commit Hash in debugInfo (DEPENDS ON #20)

[benoror]

Make it a constant for ENV (as webpack variable):

https://github.com/formly-js/angular-formly/blob/34936fa2e90d5241b87fbfc3491c290a44c59fb0/dist/formly.js#L150

  app.controller('MainCtrl', function MainCtrl(formlyVersion) {
     vm.env = {
      angularVersion: angular.version.full,
      formlyVersion: formlyVersion
    };
  });