feat(admin): add bottom navigation items and settings page to admin panel

src/shared/components/index.js

@@ -29,3 +29,4 @@ export { default as TagInput } from './TagInput';
 export { default as UserAvatar } from './UserAvatar';
 export { default as ColorPicker } from './ColorPicker.client';
 export { default as RelativeDate } from './RelativeDate.client';
+export { default as TabNav } from './TabNav';