Support saving (and loading) models to a remote bucket
# 🚀 Feature request

Support saving and loading models to and from remote buckets, e.g. Google Cloud Storage and Amazon S3.

## Motivation

Currently this is not supported, making it more difficult to train in AWS/GCP.

For reference, pandas leverages `s3fs` and `gcsfs`. A generic implementation is available through `fsspec.open()` (see [docs](https://filesystem-spec.readthedocs.io/en/latest/usage.html#higher-level)). Would the maintainers be open to that? I would be happy to contribute.<|||||>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.<|||||>This seems to be a useful feature. any thoughts about implementation of this?<|||||>[Hugging Datasets](https://huggingface.co/docs/datasets/filesystems.html) supports this feature. It really looks like a useful feature that the PreTrainedModel doesn't support today