Restructure ui into just elements and components (#3023)

This PR restructures the `ui` crate into just `elements` and
`components`.

This was already done on the `gpui2-ui` branch, just getting it onto
`main`.

Release Notes:

- N/A

---------

Co-authored-by: Nate Butler <nate@zed.dev>

crates/ui/src/components.rs

@@ -1,22 +1,44 @@
 mod breadcrumb;
+mod chat_panel;
+mod collab_panel;
+mod command_palette;
 mod facepile;
 mod follow_group;
+mod icon_button;
+mod list;
 mod list_item;
 mod list_section_header;
+mod palette;
 mod palette_item;
+mod project_panel;
+mod status_bar;
 mod tab;
+mod tab_bar;
+mod title_bar;
 mod toolbar;
 mod traffic_lights;
+mod workspace;
 
 pub use breadcrumb::*;
+pub use chat_panel::*;
+pub use collab_panel::*;
+pub use command_palette::*;
 pub use facepile::*;
 pub use follow_group::*;
+pub use icon_button::*;
+pub use list::*;
 pub use list_item::*;
 pub use list_section_header::*;
+pub use palette::*;
 pub use palette_item::*;
+pub use project_panel::*;
+pub use status_bar::*;
 pub use tab::*;
+pub use tab_bar::*;
+pub use title_bar::*;
 pub use toolbar::*;
 pub use traffic_lights::*;
+pub use workspace::*;
 
 use std::marker::PhantomData;
 use std::rc::Rc;