Typing correctness & improvements

[timoklein]

It's great that clustpy has type hints, but some of them are incorrect/outdated. Examples:

• ClustPy/clustpy/data/real_torchvision_data.py

  Lines 16 to 17 in b52d11a

  	def _get_data_and_labels(dataset: torchvision.datasets.VisionDataset, image_size: tuple) -> (
  	torch.Tensor, torch.Tensor):

  
  (torch.Tensor, torch.Tensor) is incorrect, it shout be tuple[torch.Tensor, torch.Tensor]
• https://github.com/collinleiber/ClustPy/blob/b52d11a01c9f6e5f18ccc5b92339a62a80ce7f41/clustpy/deep/_data_utils.py#L4C1-L4C34
  Should be from collections.abc import Callable as you want to rely on built-ins as much as possible.
• Same for the typing.List, use list instead.

I'm sure there are others as well. Ideally, correctness would be verified with mypy or so but I realize that this is a lot of work.