Add picture id to service catalog

[GilbertCherrie]

In Manage-IQ ui-service there is an issue where the logo of an order is not using the custom logo that users upload for catalog items.

UI-Service Logo:

Custom Logo set in UI-Classic

In order to use the custom logo in the service ui we need the api to return the image id associated with this service template / service order. The summary page in the UI-service is calling /api/service_orders/id, ideally this api call returns the image id associated with the order / template so that we can render the appropriate image in the service ui.