Moved NavPlugin types into seperate file

Summary: Moved Flow types into their own file. I will be adding more types as part of the auto complete for the navigation bar and this is to keep the code more organized.

Reviewed By: danielbuechele

Differential Revision: D16540279

fbshipit-source-id: d69ac0d05f91e9d92fcda37325c791ddc83a52c9

src/plugins/navigation/components/SearchBar.js

@@ -16,7 +16,7 @@ import {
 } from 'flipper';
 import {IconButton, FavoriteButton} from './';
 
-import type {Bookmark} from '../';
+import type {Bookmark} from '../flow-types';
 
 type Props = {|
   onFavorite: (query: string) => void,