Language refreshers aka "Coming from Python" cheatsheets

[miguelraz]

We've been missing a resource where we can point people coming in from X language help them get a good sense of the most common pitfalls they will face in Rust, per topic.

I'm proposing we take the overarching structure of the slides (delimited by Slides titles) and flesh out each section separately, per language.

I'm opening this up as a draft to see if others agree on the design of these "Coming From X" and adjust accordingly.