refactor: rename matsim network.xml.gz file to transitNetwork.xml.gz

Reason for renaming is, that in most application scenarios of the converter the transit network file will be merged with a network files which contains the network of other modes (car, pedestrian, ...) to.

src/main/java/ch/sbb/pfi/netzgrafikeditor/converter/io/matsim/TransitScheduleXmlWriter.java

@@ -16,7 +16,7 @@
 public class TransitScheduleXmlWriter implements ConverterSink<Scenario> {
 
     private static final String CONFIG_FILE = "config.xml";
-    private static final String NETWORK_FILE = "network.xml.gz";
+    private static final String NETWORK_FILE = "transitNetwork.xml.gz";
     private static final String TRANSIT_SCHEDULE_FILE = "transitSchedule.xml.gz";
     private static final String TRANSIT_VEHICLE_FILE = "transitVehicles.xml.gz";