Add new Getting Started page

Modified content in start-en.hbs to match the new theme, 
Added page specific css in content/_base,scss
Modified colours in main/_base.scss and footer/_base.scss
Modified link colours in _variables.scss 
@pjackson28 The page is meant to look consistent with the rest of the website so this is the reason why I made the breadcrumbs have a white background to blend in with the body of the entire page (and website). The reason for these changes is to keep up with the plan of having a full width for the dark blue page banner for a cleaner visual treatment. Would the full width still be able to be executed? Otherwise the page banner might end up looking like a box.