feat: added visual-codeprose experiment

[ErikBjare]

Builds upon #71

Fixes https://github.com/NeuroTechX/eeg-notebooks/issues/70

Improves some aspects of https://github.com/NeuroTechX/eeg-notebooks/issues/74

Still very WIP.

I'll likely pile on a lot of stuff on this PR, as I don't want to have to deal with branching/rebasing every time I find something small to fix.

TODO

• [x] Find some code/prose comprehension tasks
  • Fucci should have some, as well as the fMRI paper they replicated
• [x] Finish implementing the task
• [x] Make the images available for the task
  • I linked to the image source in the code, should be good enough for now.
• [x] Complete the experiment
• [x] Perform preliminary analysis
• [x] Fix issues found by mypy --check-untyped-defs
• [x] Write basic tests for common utils

[ErikBjare]

I think this is ready to merge. Will merge if CI passes.