New Augmentations

[Hendrik-code]

Piece by piece add new augmentations, verifying each time that they actually give benefits:

• Different noise augmentations (salt and pepper, snow, ...)
• Better Random Convolution augmentation (apply multiple times with same kernel, ...)
• Artifact transforms (spike, ghosting, ...)
• https://github.com/KaiyangZhou/mixstyle-release
• https://openreview.net/pdf?id=LB5F02kwAv
• TBD