Moved package-json wrapper outside implementation folder

no issue

- we're preparing the `package-json` lib to be extracted out of Ghost into
  its own package so moving the initialization wrapper outside of the
  folder makes the process a lot easier

ghost/package-json/lib/index.js

@@ -1,4 +0,0 @@
-const PackageJson = require('./package-json');
-const i18n = require('../../../../shared/i18n');
-
-module.exports = new PackageJson({i18n});