Port transforms from the classification references

- [x] [`RandomMixUp`](https://github.com/pytorch/vision/blob/5f74f0317e21f53a7ee5f61210e406c27f06a667/references/classification/transforms.py#L9) #5421
- [x] [`RandomCutMix`](https://github.com/pytorch/vision/blob/5f74f0317e21f53a7ee5f61210e406c27f06a667/references/classification/transforms.py#L92) #5421


cc @vfdev-5 @datumbox @bjuncek @pmeier