Show untagged entries count on tag list

Closes #3235

Signed-off-by: Kevin Decherf <kevin@kdecherf.com>

src/Wallabag/CoreBundle/Repository/EntryRepository.php

@@ -129,6 +129,20 @@ class EntryRepository extends EntityRepository
             ->andWhere('t.id is null');
     }
 
+    /**
+     * Retrieve the number of untagged entries for a user.
+     * 
+     * @param int $userId
+     * 
+     * @return int
+     */
+    public function countUntaggedEntriesByUser($userId)
+    {
+        return $this->getRawBuilderForUntaggedByUser($userId)
+            ->select('count(e.id)')
+            ->getSingleScalarResult();
+    }
+
     /**
      * Find Entries.
      *