Bundle targeting packs in core-sdk #9791

Once we have targeting packs for each of the shared frameworks (overview: #9744), we need to bundle the appropriate targeting packs in the .NET Core SDK. This should include the following targeting packs:

• .NET Core
• ASP.NET Core
• "DesktopUI" (Windows Forms and WPF)
• .NET Standard

These targeting packs should be laid out in the zip of the .NET Core SDK, included as bundled MSIs for the Windows installer, and expressed as package dependencies for apt-get or other packaging formats that the .NET Core SDK ships as.