Update Add Data Widget to allow configuration of layer ordering when an item is added to the Web App through this tool. Currently users can search Enterprise environment and add image services to the Web Application however, these image services default to the middle of the layer list which blocks visibility of core data and requires our end users to be 'move down' the item in the layer list. Requesting that Web App configures can default newly added layers to add the web app in particular order or that the web app be able to detect image services and automatically add them as the last item in the layer list.
