Added testing to favourite system

- Also removed some old view service references.
- Updated TopFavourites query to be based on favourites table and join
  in the views instead of the other way around, so that favourites still
show even if they have no views.

app/Http/Controllers/SearchController.php

@@ -1,6 +1,5 @@
 <?php namespace BookStack\Http\Controllers;
 
-use BookStack\Actions\ViewService;
 use BookStack\Entities\Queries\Popular;
 use BookStack\Entities\Tools\SearchRunner;
 use BookStack\Entities\Tools\ShelfContext;
@@ -10,16 +9,13 @@ use Illuminate\Http\Request;
 
 class SearchController extends Controller
 {
-    protected $viewService;
     protected $searchRunner;
     protected $entityContextManager;
 
     public function __construct(
-        ViewService $viewService,
         SearchRunner $searchRunner,
         ShelfContext $entityContextManager
     ) {
-        $this->viewService = $viewService;
         $this->searchRunner = $searchRunner;
         $this->entityContextManager = $entityContextManager;
     }