.NET (Core) stuff is implied by ManagedDesktop now, and we require only
"some .NET Framework SDK", so no need to specify explicitly as one will
be delivered by ManagedDesktop.
We do still target .NET Framework 3.5, though . . .
.NET Core 2.1 is out of support and is not used in the projects in MSBuild.sln. Removing the "Microsoft.Net.Core.Component.SDK.2.1" ID from the .vsconfig file will stop Visual Studio from complaining when .NET Core 2.1 is not installed.
Fixes#8255
Context
Developer issue while working with MSBuild.sln in Visual Studio.
Changes Made
Remove one line from .vsconfig file
Testing
Tested opening the solution before and after the .vsconfig change.
Many of the individual components listed in the first version were downloaded automatically from workloads, so this makes it more resistant to version updates necessitating changes. It also removed some extraneous files.