Create custom shapes based on existing ones

This will be a big time saver to have a tool that CUT, UNION, PUNCH, & INTERSECT multiple shapes into a single shape.

With the ability to create custom shapes in a Miro board (either through shape operations as described above, or with a pen tool, or via a third-party tool through an API/SDK), we could do more rapid low-fi wireframing and generally work in a slightly higher fidelity when creating things like journey maps in Miro.  As it stands, we need to switch to Figma if we want more than basic shapes for journey maps and other visualizations, which we tend to create collaboratively.