Reduce usage of typemaps

[DemiMarie]

When working with Smithay, the biggest pain point has invariably been the extremely heavy use of typemaps. If I pass the wrong type, I will get None with no explanation whatsoever, which is not something I expect when using Rust.

One alternative would be to make the entire crate generic over a Compositor trait that represented the compositor.

[i509VCB]

Any onlookers, see https://github.com/Smithay/wayland-rs/pull/381 for the possible changes that would lead to removal of the type maps.