Dataviz tutorial figures + slides

[dhuppenkothen]

I printed out the data visualizations for the first exercise, but they're a bit small, so maybe we can also point them towards the right folder in the repo. :)

I also added the first iteration of the slides for the tutorial.

ping @elliesch

[elliesch]

These slides look great! Thank you for adding in your pre-attentive processing slides. ☺️ I'm really looking forward to this tutorial! high fives