Allow composite model in Power BI Report Server

[angus_fry]

Released in PowerBI Desktop last November 2018, please make the "composite model" functionality available in Power BI Report Server. Key functionality requried is being able to use Direct Query against more than 1 data source, or mix Direct Query and Import in the 1 PowerBI report. Currently Power BI Desktop (optimized for Power BI Server) will force you into Import mode once you start to mix data sources, which can see you importing a lot of data. Thank you, AngusF