Removing javascript from index.html

Cleaning up the code a bit.
- The old ludo.js was basically a set of utils - so renamed it to
utils.js
- Moved all the javascript code out of the index.html and called it
ludo.js
- Moved out all the javascript to the js folder and the style.css to
the css folder
- Style.css was updated to point to the new image of the board.