Improve dashboards overview

[ale-cota]

Problem/Opportunity: Currently the dashboards overview loads maximum 3 cards even on very large screen sizes. Having a larger card doesn't actually provide additional information, so we could potentially make it more useful by loading more dashboards.

Proposed solution: Reducing the size of the the widgets to have 4 instead of 3 on a standard desktop screen (1512x1024 px) + making the tile layout responsive acc. to screen size.