Added BookmarksSidebar component

Summary:
This is another WIP. Here I construct a skeleton functional component which currently just displays that there is no bookmark information.

I have also placed the component into the layout.

Reviewed By: jknoxville

Differential Revision: D16419794

fbshipit-source-id: fe1722255bde2b8363e5514c284a242f077e5185

src/plugins/navigation/__tests__/testNavigationPlugin.node.js

@@ -12,12 +12,14 @@ import type {PersistedState} from '../';
 
 function constructPersistedStateMock(): PersistedState {
   return {
+    bookmarks: [],
     navigationEvents: [],
   };
 }
 
 function constructPersistedStateMockWithEvents(): PersistedState {
   return {
+    bookmarks: [],
     navigationEvents: [
       {
         uri: 'mock://this_is_a_mock_uri/mock/1',