VS_DOTNET_PLATFORM to overwrite the "platform" for a C# target

For example, you can now create a AnyCPU target by using
set_property(TARGET Example PROPERTY VS_DOTNET_PLATFORM "AnyCPU")
2 jobs for master in 0 seconds
latest
Status Name Job ID Coverage
  External
passed ghostflow-branch-check-master

passed ghostflow-commit-check