Image viewer (#9425)

This builds on #9353 by adding an image viewer to Zed. Closes #5251.

Release Notes:

- Added support for rendering image files
([#5251](https://github.com/zed-industries/zed/issues/5251)).

<img width="1840" alt="image"
src="https://github.com/zed-industries/zed/assets/836375/3bccfa8e-aa5c-421f-9dfa-671caa274c3c">

---------

Co-authored-by: Mikayla Maki <mikayla@zed.dev>

crates/gpui/src/gpui.rs

@@ -125,7 +125,7 @@ pub use elements::*;
 pub use executor::*;
 pub use geometry::*;
 pub use gpui_macros::{register_action, test, IntoElement, Render};
-use image_cache::*;
+pub use image_cache::*;
 pub use input::*;
 pub use interactive::*;
 use key_dispatch::*;