Mapping for legacy BOY prop show_scale

Author: tanviash

app/display/model/src/main/java/org/csstudio/display/builder/model/widgets/TankWidget.java

@@ -96,6 +96,10 @@ public boolean configureFromXML(final ModelReader model_reader, final Widget wid
                 if (element != null)
                     tank.font.readFromXML(model_reader, element);
 
+                element = XMLUtil.getChildElement(xml, "show_scale");
+                if (element != null)
+                    tank.scale_visible.readFromXML(model_reader, element);
+
                 if (XMLUtil.getChildBoolean(xml, "show_markers").orElse(true)  &&
                     (XMLUtil.getChildBoolean(xml, "show_hi").orElse(true)   ||
                      XMLUtil.getChildBoolean(xml, "show_hihi").orElse(true) ||