settings_ui: Add UI and buffer font weight controls (#15104)

This PR adds settings controls for the UI and buffer font weight
settings.

It also does some work around grouping the settings into related
sections.

Release Notes:

- N/A

crates/ui/src/components.rs

@@ -18,6 +18,8 @@ mod popover_menu;
 mod radio;
 mod right_click_menu;
 mod setting;
+mod settings_container;
+mod settings_group;
 mod stack;
 mod tab;
 mod tab_bar;
@@ -33,7 +35,7 @@ pub use checkbox::*;
 pub use context_menu::*;
 pub use disclosure::*;
 pub use divider::*;
-use dropdown_menu::*;
+pub use dropdown_menu::*;
 pub use facepile::*;
 pub use icon::*;
 pub use indicator::*;
@@ -47,6 +49,8 @@ pub use popover_menu::*;
 pub use radio::*;
 pub use right_click_menu::*;
 pub use setting::*;
+pub use settings_container::*;
+pub use settings_group::*;
 pub use stack::*;
 pub use tab::*;
 pub use tab_bar::*;