Remove from __init__

Hi,

I only want to use the dataset, but it crashes since I don't want to install haiku. I have to comment on the ```clrs.__init__.py``` the following lines:

```python

# from clrs import models

from clrs._src import algorithms
from clrs._src import clrs_text
# from clrs._src import decoders
# from clrs._src import processors
from clrs._src import specs

from clrs._src.dataset import chunkify
from clrs._src.dataset import CLRSDataset
from clrs._src.dataset import create_chunked_dataset
from clrs._src.dataset import create_dataset
from clrs._src.dataset import get_clrs_folder
from clrs._src.dataset import get_dataset_gcp_url

from clrs._src.evaluation import evaluate
from clrs._src.evaluation import evaluate_hints

from clrs._src.model import Model

from clrs._src.probing import DataPoint
from clrs._src.probing import predecessor_to_cyclic_predecessor_and_first

# from clrs._src.processors import get_processor_factory
```

and with that change it doesn't complain anymore when I import ```from clrs._src.clrs_text.huggingface_generators import clrs_generator``` and produces correctly the dataset. I wonder if it might be desirable for you too to make sure the code doesn't require you to install packages that are irrelevant for the dataset generation.