Introduce support to embedd the scorecards as a JS widget

[fpietrosanti]

This ticket is to Introduce support to embedd the scorecards as a JS widget in order to enable third party organizations to integrate the scorecards into specific campaign websites (ie: a campaign dedicated/focused on italian media, with a single-page-website for the campaign in italian, integrating the widget).

The widget should provide the ability to have country selectors, in order to display only media of a specific country.