General ImageVisualizerCallback

[dxoigmn]

What does this PR do?

Writing images to disk a bad idea when we can write images to Tensorboard. This PR also genericizes PerturbedImageVisualizer into a configurable ImageVisualizer so that one can visualize perturbations, inputs, and perturbed inputs.

Type of change

Please check all relevant options.

• [ ] Improvement (non-breaking)
• [ ] Bug fix (non-breaking)
• [ ] New feature (non-breaking)
• [ ] Breaking change (fix or feature that would cause existing functionality to not work as expected)
• [ ] This change requires a documentation update

Testing

Please describe the tests that you ran to verify your changes. Consider listing any relevant details of your test configuration.

• [ ] Test A
• [ ] Test B

Before submitting

• [ ] The title is self-explanatory and the description concisely explains the PR
• [ ] My PR does only one thing, instead of bundling different changes together
• [ ] I list all the breaking changes introduced by this pull request
• [ ] I have commented my code
• [ ] I have added tests that prove my fix is effective or that my feature works
• [ ] New and existing unit tests pass locally with my changes
• [ ] I have run pre-commit hooks with pre-commit run -a command without errors

Did you have fun?

Make sure you had fun coding 🙃