Integrate Excalidraw #449
Description
Is your feature request related to a problem? Please describe.
Diagramming has been a frequent feature request for MicroPad (i.e. #97). This seems like a good way to do it.
Describe the solution you'd like
Add a new element type which is basically just: https://docs.excalidraw.com/docs/@excalidraw/excalidraw/installation
Describe alternatives you've considered
Mermaid JS integration in the parser. This is easier because adding external libs to our markdown sandbox is annoying.