Mainline GPUI2 UI work (#3099)

This PR mainlines the current state of new GPUI2-based UI from the
`gpui2-ui` branch.

Included in this is a performance improvement to make use of the
`TextLayoutCache` when calling `layout` for `Text` elements.

Release Notes:

- N/A

---------

Co-authored-by: Nate Butler <iamnbutler@gmail.com>
Co-authored-by: Antonio Scandurra <me@as-cii.com>

crates/ui/src/components.rs

@@ -9,17 +9,22 @@ mod editor_pane;
 mod facepile;
 mod icon_button;
 mod keybinding;
+mod language_selector;
 mod list;
+mod multi_buffer;
 mod palette;
 mod panel;
 mod panes;
 mod player_stack;
 mod project_panel;
+mod recent_projects;
 mod status_bar;
 mod tab;
 mod tab_bar;
 mod terminal;
+mod theme_selector;
 mod title_bar;
+mod toast;
 mod toolbar;
 mod traffic_lights;
 mod workspace;
@@ -35,17 +40,22 @@ pub use editor_pane::*;
 pub use facepile::*;
 pub use icon_button::*;
 pub use keybinding::*;
+pub use language_selector::*;
 pub use list::*;
+pub use multi_buffer::*;
 pub use palette::*;
 pub use panel::*;
 pub use panes::*;
 pub use player_stack::*;
 pub use project_panel::*;
+pub use recent_projects::*;
 pub use status_bar::*;
 pub use tab::*;
 pub use tab_bar::*;
 pub use terminal::*;
+pub use theme_selector::*;
 pub use title_bar::*;
+pub use toast::*;
 pub use toolbar::*;
 pub use traffic_lights::*;
 pub use workspace::*;