Add a custom set of images
We will eventually ask a designer to make a custom TOTEM icon set, which should be used in the graph-editor-xblock. To prove we can do this, take a custom set of images and try to add it.
Bonus points if we can get an SVG icon pack, so it's infinitely scalable.
Note that draw.io (which has some extra extensions upon the open source 'grapheditor' thing we built upon) supports custom libraries, but I couldn't really find any downloadable examples with a quick DDG search...