Let extension contribute to ports context

and return useful info from port label command
Part of microsoft/vscode-remote-release#4433

src/vs/workbench/api/common/menusExtensionPoint.ts

@@ -182,6 +182,11 @@ const apiMenus: IAPIMenu[] = [
 		id: MenuId.TimelineItemContext,
 		description: localize('view.timelineContext', "The Timeline view item context menu")
 	},
+	{
+		key: 'ports/item/context',
+		id: MenuId.TunnelContext,
+		description: localize('view.tunnelContext', "The Ports view item context menu")
+	}
 ];
 
 namespace schema {