Adding training jupyter notebooks

[paganpasta]

Adding a sample training notebook (preferably on each network) on Imagenette demonstrating some different techniques. For example, different optimizers, transfer learning, distillation etc. Open to discussions!

• ~~Image Classification~~
• [x] Transfer Learning
• [x] Generating Adversarial Examples
• [x] Visualising Attentions (Vision Transformer)
• [ ] Class activation maps
• [ ] Training a GAN
• [ ] Training a Diffusion Model