adapter.xml: Apply customizing pattern with class methods of json_deserialization to xml_deserialization

In the aas.adapter.json.json_deserialization we introduced an elegant pattern to allow customizing the parser behaviour by subclassing the AASFromJsonDecoder class and overriding its constructor methods. This is used by the CouchDB adapter for example, to construct subclasses of the normal AAS model classes.

We could apply the same pattern to the xml_deserialization module.