Improved status updates from trainer

[denniswittich]

Communication changes

• No longer send redundant fields (like the hyperparameters, ... ) with the trainer updates (they are send with the training updates)
• Change type of hyperparameters to a dict
• Add fields trainer_name and best_epoch to DC TrainingOut - used to sync the training

Internal changes:

• removes the internal DC TrainingData and moves its fields (image_data, categories,skipped_image_count,hyperparameter) to the Training DC. The class added non-required complexity!