gpui: Add Wayland support (#7664)

This PR adds Wayland support to gpui using
[wayland-rs](https://github.com/Smithay/wayland-rs). It is based on
[#7598](https://github.com/zed-industries/zed/pull/7598).

It detects Wayland support at runtime by checking the existence of the
`WAYLAND_DISPLAY` environment variable. If it does not exist or is
empty, the X11 backend will be used. To use the X11 backend in a Wayland
session (for development purposes), you just need to unset
WAYLAND_DISPLAY (`WAYLAND_DISPLAY= cargo run ...`).

At the moment it only creates the window and renders the initial content
provided by `BladeRenderer`, so it can run "Hello world" example.


![image](https://github.com/zed-industries/zed/assets/40907255/1655bc64-4d36-4178-9851-bfe42f03f716)

Todo:
- [x] Add basic Wayland support.
- [x] Add window resizing.
- [x] Add window closing.
- [x] Add window updating.
- [ ] Implement input handling, fractional scaling, and support other
Wayland protocols.
- [ ] Implement all unimplemented todo!(linux).
- [ ] Add window decorations or use custom decorations (like on MacOS).
- [ ] Address other missing functionality.

Release Notes:
- N/A

---------

Co-authored-by: gabydd <gabydinnerdavid@gmail.com>
Co-authored-by: Mikayla Maki <mikayla@zed.dev>

crates/gpui/src/platform/linux/wayland.rs

@@ -0,0 +1,7 @@
+pub(crate) use client::*;
+pub(crate) use client_dispatcher::*;
+
+mod client;
+mod client_dispatcher;
+mod display;
+mod window;