In Visual Studio 2017 Community, I can't develop SSIS packages out of the box like I could with Visual Studio 2015. I went looking, and they're doesn't appear to be a SSIS SSDT for VS2017.
Instead, I had to install VS2017 Community Edition, and head to the marketplace to find tools that I used to be able to get as a part of the SSDT download.
Report Projects for Visual Studio
Analysis Services Modeling Projects
But I still need to edit SSIS packages, which, according to the blog at this MSDN link, support is "forthcoming".
Argh.
Back to Visual Studio 2015 for a while longer, I guess.