Added option to split PDF into multiple parts and merge into one PDF (#841)

* Added option to split PDF into multiple parts and merge into one PDF

* Use the mergeDocuments method in MergeController to implement merging

---------

Co-authored-by: Eric <71648843+sbplat@users.noreply.github.com>

pipeline/defaultWebUIConfigs/split-rotate-auto-rename.json

@@ -6,7 +6,8 @@
       "parameters": {
         "horizontalDivisions": 2,
         "verticalDivisions": 2,
-        "fileInput": "automated"
+        "fileInput": "automated",
+        "merge": false
       }
     },
     {
@@ -30,4 +31,4 @@
   },
   "outputDir": "{outputFolder}",
   "outputFileName": "{filename}"
-}
+}