Add ECOC (Error correcting output codes)

**Describe the solution you'd like**
ECOC is available as Trainer/Classifier

**Describe alternatives you've considered**
Using other frameworks like scikit-learn via dllimport

**Additional context**
it might appear under a different name in some sources, for example: (error correcting) multiclass SVM.

https://machinelearningmastery.com/error-correcting-output-codes-ecoc-for-machine-learning/