Streaming dataset based on dl_manager.iter_archive/iter_files are not reset correctly
Hi ! When iterating over a streaming dataset once, it's not reset correctly because of some issues with `dl_manager.iter_archive` and `dl_manager.iter_files`. Indeed they are generator functions (so the iterator that is returned can be exhausted). They should be iterables instead, and be reset if we do a for loop again:

```python
from datasets import load_dataset
d = load_dataset("common_voice", "ab", split="test", streaming=True)

i = 0
for i, _ in enumerate(d):
    pass
print(i)  # 8
# let's do it again
i = 0
for i, _ in enumerate(d):
    pass
print(i)  # 0
```