Support broader range of GeoJSON in schema generation

[sergei-maertens]

Robin added support for drawing multiple kinds of shapes on maps, which is a subset of the GeoJSON spec. This is more extensive than the current latitude/longitude array that is support for a single marker - see #2177 and #2178

Keep in mind that the component settings also determine the available shapes - this will be a polymorphic structure too (using anyOf).