Fix pdfa conversion (#1907)

* fix: use gs to convert to pdfa and return output by reading file as bytes

* feat: update translation files for pdfToPDFA.credit

* Hardening suggestions for Stirling-PDF / fix_pdfa_conversion (#1908)

Switch order of literals to prevent NullPointerException

Co-authored-by: pixeebot[bot] <104101892+pixeebot[bot]@users.noreply.github.com>

---------

Co-authored-by: pixeebot[bot] <104101892+pixeebot[bot]@users.noreply.github.com>

scripts/replace_translation_line.sh

@@ -0,0 +1,10 @@
+#!/bin/bash
+
+translation_key="pdfToPDFA.credit"
+old_value="OCRmyPDF"
+new_value="ghostscript"
+
+for file in ../src/main/resources/messages_*.properties; do
+  sed -i "/^$translation_key=/s/$old_value/$new_value/" "$file"
+  echo "Updated $file"
+done