package.json should specify an empty build step

Problem/Motivation

In order to have working es6 => es5 transpiling on the testbot we will need them to run a build step.
Before we can do that though we need to have a valid entry in the file, so the testbot can run the build step, before the transpiling patch is in.

Proposed resolution

Add an empty run script into the package.json file which does "nothing" called build:js

Remaining tasks

User interface changes

API changes

Data model changes