Lower number of categories of widget on the right side of the tab designer

Tab widgets palette, summary widgets palette, schema (??), standalone, static,advanced ... we should have fewer categorie, here is a proposal:

• Static widgets palette (which should also include the "Summary widgets palette" one, minus the Custom Actions widget, and the Standalone widget )
• Configurable widgets palette: Layout, Content view, Custom Actions (they all leverage resources that are declared somewhere else in Studio)
• Advanced: Template widget and Generic widget (we should withdraw the layout widget, shouldn't we ? )

We should have the same categories on the summary tab.