M2M100 support for ONNX export
# What does this PR do?

Enable ONNX export for M2M100 models for the following tasks:

- default
- default-with-past
- seq2seq-lm
- seq2seq-lm-with-past

Related issue: #15060 
The export for `seq2seq-lm` and `seq2seq-lm-with-past` is failing due to 
```
RuntimeError: Exporting model exceed maximum protobuf size of 2GB. Please call torch.onnx.export without setting use_external_data_format parameter.
```
The `OnnxConfig.use_external_data_format` finds that the size is ok... working on it!

Also the export works for `valhalla/m2m100_tiny_random`, which is very small, meaning that the export is working, so it is related to the model size.<|||||>This issue has been automatically marked as stale because it has not had recent activity. If you think this still needs to be addressed please comment on this thread.

Please note that issues that do not follow the [contributing guidelines](https://github.com/huggingface/transformers/blob/master/CONTRIBUTING.md) are likely to be ignored.<|||||>The try / except change aims at poiting the user to use a more recent torch version to (possibly) be able to export the model as the protobuf issue seems solved starting from torch 1.10 (when not specifying the deprecated arguments).