Expose arm resources from Graph API

We now have this senario that we need to implement a graph api in the backend service and return a list of azure resource to the UX side, like subscription, resource groups, vnets, subnets, not sure if there is any concern about this from the graph side. (why we don't call arm api directly from the ux is because the resource is from another customer account, and we can't login two account from the ux side this time).