Animations for `mutate()`, `summarize()`, `group_by()` and `ungroup()`

[andrewheiss]

To address #31, here are 7 new animations in the style of the other tidyexplain animations showing mutate(), summarize(), group_by() and ungroup()!

https://www.andrewheiss.com/blog/2024/04/04/group_by-summarize-ungroup-animations/

It was too tricky to do these with {gganimate} because they all involve multiple sets of dataframes, so they're made with After Effects instead. All the raw files are accessible there too (mp4, gif, etc), though the GIFs might need to be compressed.

[gadenbuie]

This is so so so awesome, thanks for sharing @andrewheiss!!