Extract TabBar component (#3613)

This PR extracts a new `TabBar` component from the tab bar
implementation in the workspace.

Release Notes:

- N/A

crates/ui2/src/components.rs

@@ -14,6 +14,7 @@ mod popover_menu;
 mod right_click_menu;
 mod stack;
 mod tab;
+mod tab_bar;
 mod tooltip;
 
 #[cfg(feature = "stories")]
@@ -35,6 +36,7 @@ pub use popover_menu::*;
 pub use right_click_menu::*;
 pub use stack::*;
 pub use tab::*;
+pub use tab_bar::*;
 pub use tooltip::*;
 
 #[cfg(feature = "stories")]