[ACA-3672] - added server order for document -list (#5899)

* [ACA-3672] - added sorting server side for document-list

* [ACA-3672] - added and fixed unit tests for backend order

* [ACA-3672] - fixed failing test

* [ACA-3672] - regenerated doc and renamed variable

Co-authored-by: Vito Albano <vitoalbano@Vitos-MacBook-Pro.local>

lib/core/datatable/data/data-column.model.ts

@@ -42,4 +42,5 @@ export interface DataColumn {
     copyContent?: boolean;
     editable?: boolean;
     focus?: boolean;
+    sortingKey?: string;
 }