IterableDataset formatting in numpy/torch/tf/jax
This code now returns a numpy array:
```python
from datasets import load_dataset

ds = load_dataset("imagenet-1k", split="train", streaming=True).with_format("np")
print(next(iter(ds))["image"])
```

It also works with "arrow", "pandas", "torch", "tf" and "jax"

### Implementation details:

I'm using the existing code to format an Arrow Table to the right output format for simplicity.
Therefore it's probbaly not the most optimized approach.

For example to output PyTorch tensors it does this for every example:

python data -> arrow table -> numpy extracted data -> pytorch formatted data

### Releasing this feature

Even though I consider this as a bug/inconsistency, this change is a breaking change.
And I'm sure some users were relying on the torch iterable dataset to return PIL Image and used data collators to convert to pytorch.

So I guess this is `datasets` 3.0 ?

### TODO

- [x] merge https://github.com/huggingface/datasets/pull/5072
- [ ] docs
- [ ] tests

Close https://github.com/huggingface/datasets/issues/5083