SimCLRv2 for arbitrary input channels

[tnw-chatc]

Change Description

• My PR includes a link to the issue that I am addressing

Solution Description

• Added SimCLRv2 model that handles an arbitrary number of input channels, as opposed to SimCLR that exclusively handles three due to the feature extractor being resnet18
  • Both SimCLR and SimCLRv2 share the same config parameters
  • Removed Grayscale and ColorJitter from augmentation since it's only for three-channel input
  • Added GaussianBlur and GaussianBlur to augmentation
• (TEMPORARY) Forced the model to use a custom-defined criterion