nimbusml should print training progress in the console

[sfilipi]

I am trying a long-ish to train model; takes about 4 minutes, and I find the absence of any progress reporting unsettling. I think the same progress reporting that is printed in ML.NET prior to PR #923 should be available here too.

[montebhoover]

Senja, thanks for opening the issue in ML.NET: dotnet/machinelearning#1367.

If that issue does not gain traction, perhaps we can increase the verbosity of the ML.NET environment with something like mlContext.Log += Console.WriteLine?