Bug 332260

This task is about implementing full support for the KML extrude tag. It can occur as a child element of <Point>, <Polygon>, <LineString> and <LinearRing>. See https://developers.google.com/kml/documentation/kmlreference for details.
- Fix KmlextrudeTagHandler::parse, which does a faulty boolean check if( parentItem.nodeAs<GeoDataGeometry>() ). Change both checks in that area to use
parentItem.is<GeoData...>() for all fours elements (GeoDataPoint, GeoDataLineString, GeoDataLinearRing, GeoDataPolygon). Assign them the extrude value as necessary.
- Extend all Kml*TagWriter.cpp files for Point, LineString, LinearRing and Polygon to write the extrude tag if extrude is active (so either <extrude>1</extrude> ends up in the KML file or nothing).
- Extend the .kml files in tests/data/ to have at least one instance with <extrude>1</extrude> for all four tags

Make sure to compile Marble with the following cmake options enabled: BUILD_MARBLE_TESTS=TRUE, BUILD_MARBLE_TOOLS=TRUE. Execute tests/TestGeoDataWriter and make sure no errors come up. Use tools/kml2kml to analyze errors and fix the tag writers, if needed. Submit a review request at https://git.reviewboard.kde.org with the marble group as reviewers.

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