Add support for animated visualizations

[adamconkey]

I'd like to be able to have visualizations that show animations of the algorithms in progress. I know that egui_plot supports dynamic visualizations so would just have to look more into that and add some basic GUI controls to allow stepping through the algorithm and also playing at different speeds.

Can start with the triangulation visualization that's doing ear search. Can also do the trapzoidization algorithm in #14 once that's implemented.