KML: only blue fill and stroke

Polygons/lines have only standard blue colors. Individually styling every polygon is hard and i'm 100% sure there's an easier way to this.

Start by locating the KML handling entry point for polygon and line styling; the issue does not name a file or test. Determine how the current standard blue fill and stroke are selected, then verify that styling can be customized without individually editing every polygon or line.

Written by the indexing model from the issue text.