Figure out how to make xfce4-find-cursor work

xfce4-find-cursor is an accessibility tool that draws an animated bullseye-like effect around the cursor so the user can find it.

Since the cursor position is considered "privileged" on Wayland, I don't think it's a good idea to just expose that over a custom protocol. However, since it's fairly simple, the animation could be moved into the compositor, and triggered with a custom protocol.