[C++] Mechanism for throttling remote filesystems to avoid rate limiting

### Describe the enhancement requested

In the current implementation of at least the S3 filesystem, it's possible to hit AWS' rate limiting and this makes it hard to use a function like `pyarrow.parquet.write_dataset` to write highly partitioned datasets to S3. When the rate limit is hit during writing, the user receives an HTTP 503 with a "SLOW_DOWN" error and the request needs to be retried. I would guess any other cloud storage provider (ie GCS) would behave similarly though I haven't tested.

There are a few things that could be done to address this issue:

- Add logic to the S3 implementation to deal with the issue directly
- Implement a generic `ThrottledFilesystem` that can wrap another `Filesystem` and throttle certain calls (ie writes)
- Expose the existing `SlowFileSystem` to Python/R and possibly tweak its implementation to suit this use case

### Component(s)

C++

Start by reading the S3 filesystem implementation and the existing SlowFileSystem entry point, then trace how pyarrow.parquet.write_dataset reaches remote filesystem writes. Compare the three proposed approaches and confirm the intended scope with maintainers; the issue does not yet define which design or tests would constitute done.

Written by the indexing model from the issue text.