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/docker/docker_vm.py

@@ -109,6 +109,7 @@ class DockerVM(BaseNode):
     def __json__(self):
         return {
             "name": self._name,
+            "usage": self.usage,
             "node_id": self._id,
             "container_id": self._cid,
             "project_id": self._project.id,