Add API to automate element legend generation #21
Description
The problem
WebVOWL would benefit from an element legend, as described in WebVOWL/WebVOWL-Reimagined#29.
We'd like to avoid manually inserting images of each node type. However, the renderer in RustGrapher currently does not support exposing a visualization of the rendered node types.
Idea
Figure out whether it is possible to automatically export a picture in wgpu. Maybe some crate exist to do this?