New node information dialog to display general, usage and command line information.

Ref https://github.com/GNS3/gns3-gui/issues/2662 https://github.com/GNS3/gns3-gui/issues/2656

gns3server/compute/dynamips/nodes/router.py

@@ -143,6 +143,7 @@ class Router(BaseNode):
     def __json__(self):
 
         router_info = {"name": self.name,
+                       "usage": self.usage,
                        "node_id": self.id,
                        "node_directory": os.path.join(self._working_directory),
                        "project_id": self.project.id,