Fix Dataloader by adding Sampler.

[adendek]

Enhance data loader utils by implementing sampler. The idea is to replace it with something similar to the PyTorch sampler.

The following resources may be useful:

1. https://medium.com/geekculture/pytorch-datasets-dataloader-samplers-and-the-collat-fn-bbfc7c527cf1
2. https://pytorch.org/docs/stable/_modules/torch/utils/data/sampler.html#RandomSampler