Add Webpack bundler

Added a NPM packages.json list which manages
 JavaScript packages. Most important packages added
 is the Webpack package which acts as an assets
 bundler.
It is added in its most basic working form. This
 includes additional settings in `settings.py`
 and the template tags in `base.html`.
Please read the updated Readme.md to easily get
 started using Webpack for your new assets.