Add support of multiple geometries in GeoJSON

[lgoltz]

GeoJSON supports only one geometry object per feature. GML and also deegree is not limited to one geometry collection per feature type. With the export of GeoJSON in a WFS GetFeature response as well as WMS GetFeatureInfo request (#1582) an error occurs if a feature contains more than one geometry collection.

deegree should handle multiple geometry properties. Possible solutions are:

1. Configure the geometry returned by GeoJSON. Other geometries are skipped in the GeoJSON export.
2. Configure the geometry returned by GeoJSON as main geometry. Other geometries are exported in the properties array.