Add more default dashboards or add a plugin to the Marketplace that provides further dashboards

This was a suggestion by a user at the meetup. There could be for instance a SEO dashboard beside the default dashboard that shows especially reports that are important for SEO optimization. Maybe there could be even more default dashboard.

Alternatively we could add a plugin on the Marketplace that adds a set of dashboards to the Piwik instance. Either a user can select in which ones he is interested in or we install all of them directly