Fixed: Added Various Missing Translations

cleanup en.json of unused translates

Fixes #1397

Closes Sonarr PR # 4791 'Fixed: Better wording of MissingFromDisk'

frontend/src/Activity/Queue/Queue.js

@@ -223,14 +223,14 @@ class Queue extends Component {
           {
             !isRefreshing && hasError &&
               <div>
-                Failed to load Queue
+                {translate('FailedToLoadQueue')}
               </div>
           }
 
           {
             isAllPopulated && !hasError && !items.length &&
               <div>
-                Queue is empty
+                {translate('QueueIsEmpty')}
               </div>
           }