Implement an article with hard coded content

Setting up an article pages that is styled utilising the govuk frontend toolkit and govuk elements. 
Implementing my preferred BEM and folder structure to make the code base maintainable.
I'm temporarily using the styles from gov_uk static to style the article content.

@jiannis @gjvis @andrewgarner 
These should be in `vendor/assets`. By placing them there you are calling them out as 3rd party.