Is your feature request related to a problem? Please describe.
As we already set up MONAI workflow based on our own SupervisedTrainer, seems no need to keep the ignite trainer APIs which were developed at the beginning of the project.
Would be nice to deprecate them:
https://github.com/Project-MONAI/MONAI/blob/dev/monai/engines/multi_gpu_supervised_trainer.py