Activation visualization function

New configurations for dataset tbx11k were added for visualization. New scripts have been added for visualizing the activations by using the pre-pytorch-lightning models. The visualizations are generated through the pytorch-grad-cam library: https://github.com/jacobgil/pytorch-grad-cam It is unclear if this library works with the pytorch ligthning models, and the part of the visualize.py script that needs to be presumingly adapted to work with lightning models has been commented accordingly. No automatic recognition of model type has been implemented, so this needs to be implemented manually later on when the lightning module works fully. Other scripts for evaluating the metrics from the visualization script and generating side-by-side comparisons of different visualization methods have been added too.