Pre-Train models on CIFAR-100

[shan18]

Pre-train all models on CIFAR100 so that it can be given as a transfer learning option.

Train on torch==1.5.1 and after training, upload models to S3

[rvk007]

Trained the following model on CIFAR100:

• Resnet18: 61.34%
• Resnet34: 62.16%
• MobileNet v2: 52.22%