Add new GLUE example with no Trainer.
# What does this PR do?

This PR adds a new GLUE example that does not use the `Trainer`, leveraging [accelerate](https://github.com/huggingface/accelerate) for the distributed training. The necessary instructions are added in the text-classification README.

cc @JetRunner as it should be of interest to you.
This kind of logging is very useful for researchers. Let's add them back?

https://github.com/google-research/bert/blob/master/run_classifier.py#L871<|||||>In a nutshell, I'll burst into tears if we can just have Google's `run_classifier.py` back but with `accelerate` :)<|||||>Maybe we should tag other researchers (even external) to give some feedback. cc @VictorSanh @TevenLeScao <|||||>Addressed most of your comments except the logging/saving steps. I do not have time to add this right now, so I suggest we merge the current version and someone from the community can finish it.