ENH: Respect sort and limit arguments

These parameters are defined in the PHPDocs for `Report` and are technically part of the method signature. They should be respected and in the case of the new default limit in silverstripe/silverstripe-reports#139 this could have performance ramifications for large datasets.

src/Reports/PagesWithoutReviewScheduleReport.php

@@ -107,7 +107,7 @@ public function columns()
      *
      * @return SS_List
      */
-    public function sourceRecords($params = [])
+    public function sourceRecords($params = [], $sort = null, $limit = null)
     {
         Versioned::set_stage(Versioned::DRAFT);
 
@@ -125,7 +125,13 @@ public function sourceRecords($params = [])
             ));
         }
 
-        $records->sort("ParentID");
+        if ($sort !== null) {
+            $sort = 'ParentID';
+        }
+        $records->sort($sort);
+        if ($limit !== null) {
+            $records = $records->limit($limit);
+        }
         $records = $records->toArray();
 
         // Trim out calculated values