Official Camunda modeller can be used with new templates [OW-571]

Previously you had to use the extended OMN Camunda Modeler to support the OMN workflow templates. With our new templates there is no need to use this special modeler anymore, you can just use the official modeler (cp. OW-571 Replace apollon camunda modeler by camunda default modeler (Collector)).

The reason of the OMN apollon camunda modeler was to apply a currently unsupported type of listener by template. We replaced this type of listener by an BpmnParseListener as ProcessEnginePlugin to alter the bpmn and add the listener logic there when it gets uploaded.