An updated look for Documents

To make the coloured folder icons distinct and easy to separate, we decided on a flatter look for the folder icons. Empty folders are shown with just an outline. We also updated some other icons in Documents to align with the new look of the folder icons. Especially the icons for document sets, template folders, document baskets and the recycle bin to Gove the navigation tree a unified look.

We also updated the thumbnail view so that all rows are the same height to make it easier on the eye.