unstable: add xcursor-configuration
Clients are responsible for loading and setting cursors. For this purpose they often use XCursor images via the libwayland-cursor library. However clients have no way to know the user's preferred theme and size. This results in inconsistent cursors across clients (e.g. cursor growing bigger when entering a surface).
This protocol fixes this issue by sending the user's XCursor preferences to the client. It also allows for per-device cursor configuration.
Previously submitted on the mailing list: https://patchwork.freedesktop.org/series/50948/