Add Tabs container

Summary: Adding an additional style for tabs on top of a container, similar to the ones used in macOS

Reviewed By: passy

Differential Revision: D17450843

fbshipit-source-id: 6b58c2aa290e0221d917e60bb3ac0751f77ea1ce

src/ui/index.tsx

@@ -64,6 +64,7 @@ export {
 // tabs
 export {default as Tabs} from './components/Tabs';
 export {default as Tab} from './components/Tab';
+export {default as TabsContainer} from './components/TabsContainer';
 
 // inputs
 export {default as Input} from './components/Input';