Feat: Reverse-pages for mulit-pdf

- Added new state pdfDocs: [ ]
- Made tweaks for new state in fileHandler.ts

src/js/config/pdf-tools.ts

@@ -62,4 +62,5 @@ export const multiFileTools = [
   'tiff-to-pdf',
   'alternate-merge',
   'linearize',
+  'reverse-pages',
 ];