Add HF Dataset components

[NielsRogge]

This PR adds boilerplate HFDatasetLoaderComponent and HFDatasetTransformComponent classes.

Questions:

• in the Datasets library, there's a distinction between a Dataset and a DatasetDict. The latter is just a dictionary of several Dataset instances, with keys like "train", "validation", "test". I assume the index could be stored as a Dataset, whereas data sources can be either a Dataset or a DatasetDict.
• if you use load_dataset without providing a split (like "train", "validation"), this method returns a DatasetDict instead of a Dataset. So was wondering how we could handle these splits a user might have.

To do:

• add an example

[NielsRogge]

Also was wondering whether we could have a better name (DatasetsDataset might not be the best name)

[RobbeSneyders]

Any reason not to just go for HFDataset?

[NielsRogge]

load_dataset also supports things like multiprocessing (if there are multiple CPU cores) and streaming (loading data on-the-fly), not sure if we want to leverage those too

[NielsRogge]

@RobbeSneyders so the pipeline fails because datasets is not in the dependencies of pyproject.toml. However I don't think it makes sense to make this a hard dependency, which is why I was arguing for soft dependency checks depending on which components a user might want to use. Thoughts?

[RobbeSneyders]

I think handling soft dependencies would be good indeed. I would add it as a dependency in this PR, and then open a new PR where we implement the soft dependency checks for both datasets and pandas.

[RobbeSneyders]

Seems like I was a bit too strict with the allowed licenses. We can allow weak-copyleft licenses as well.

You can add the following ones and it will fix the pipeline:

• GNU Library or Lesser General Public License (LGPL)
• GNU Lesser General Public License v2 (LGPLv2)
• GNU Lesser General Public License v2 or later (LGPLv2+)
• GNU Lesser General Public License v3 (LGPLv3)
• GNU Lesser General Public License v3 or later (LGPLv3+)
• Mozilla Public License 1.0 (MPL)
• Mozilla Public License 1.1 (MPL 1.1)
• Mozilla Public License 2.0 (MPL 2.0)
• The Unlicense (Unlicense)

[RobbeSneyders]

Thanks! LGTM.

Can you just remove the pylint: disables and resolve the conflict?