.NET: add support for passing arguments to mobile apps at launch

[rolfbjarne]

Currently we don't honor arguments like this for mobile apps (iOS, tvOS):

dotnet run project.csproj -- arg1 arg2

We should look into fixing this.

This means getting these arguments from the build somehow, and converting them into mlaunch arguments (--argument=arg1 --argument=arg2).

It should also be possible to do the same thing for dotnet build /t:Run (maybe by setting a new property?)