Augmentations on data pipeline

Some suggestions on how to augment the input Sentinel-2 imagery dataset before passing into the neural network model from @srmsoumya:

- [ ] Cloud augmentation using [`imageaug`](https://imgaug.readthedocs.io/en/latest/source/overview/weather.html)
- [ ] [Cutmix](https://arxiv.org/abs/1905.04899v2)
- [ ] [MixMatch](https://arxiv.org/abs/1905.02249v2)

Note that we'll need to pay attention the the burned and non-burned areas when applying these augmentations.