Extend FdoWmsOvClassDefinition with a property for CRS name to be used as spatial context name

[kwi]

On the WMS provider, every child class inherits the properties from the base class, when one exist. As the geometry property contains the spatial context, every class inherits the spatial context association from the base class. This leads to the fact that even when the child class has the default WMS CRS (EPSG:4326) assigned, but not the base class, the child will get the spatial context with the CRS from the base class. This is then a different one than the default CRS.

It can be verified with this link: ​https://mapsengine.google.com/12700653833057327143-17379123781214007005-4/wms/?version=1.3.0

The WMS service itself has the EPSG:4326 as the spatial context. So all feature classes in FDO have a different spatial context as the WMS service itself, which can lead to problems.

The proposed fix is to give the FdoWmsOvClassDefinition a spatial CRS property, to be independent from the geometry property of the class itself. This CRS of the FdoWmsOvClassDefinition can be different than the one from the geometry property. Two methods to Set & Get the CRS will also be added. So that 3rd party applications can use the CRS property of the class definition additionally to the CRS of the geometry property.