Core: Introduce PDF Import-Export dialog (#20860)

* Core: Introduce PDF Import-Export dialog

Currently, we only have hardcoded exporting to one pdf version, which
leads to (as in one of the below issues) to problems, such as
non-transparent layers, which are by default not supported in PDF/A-1b.

So, this patch adds an option to the user to select their preferred PDF
version by introducing new dialog under Import-Export in Preferences,
and allowing to update that version before exporting.

* Core: Add informational messages regarding selected PDF format

* Gui: Handle Qt < 6.8 unsupported PDF format

* Gui: Switch PDF export prefs dialog to use tr()

* Gui: Remove center alignment of PDF version description

---------

Co-authored-by: Chris Hennes <chennes@pioneerlibrarysystem.org>

src/Gui/EditorView.cpp

@@ -57,6 +57,8 @@
 #include <Base/Interpreter.h>
 #include <Base/Parameter.h>
 
+#include <Gui/PreferencePages/DlgSettingsPDF.h>
+
 
 using namespace Gui;
 namespace Gui
@@ -511,9 +513,10 @@ void EditorView::printPdf()
                                     QStringLiteral("%1 (*.pdf)").arg(tr("PDF file")));
     if (!filename.isEmpty()) {
         QPrinter printer(QPrinter::ScreenResolution);
-        // setPdfVersion sets the printied PDF Version to comply with PDF/A-1b, more details under:
+        // setPdfVersion sets the printed PDF Version to what is chosen in
+        // Preferences/Import-Export/PDF more details under:
         // https://www.kdab.com/creating-pdfa-documents-qt/
-        printer.setPdfVersion(QPagedPaintDevice::PdfVersion_A1b);
+        printer.setPdfVersion(Gui::Dialog::DlgSettingsPDF::evaluatePDFVersion());
         printer.setOutputFormat(QPrinter::PdfFormat);
         printer.setOutputFileName(filename);
         printer.setCreator(QString::fromStdString(App::Application::getNameWithVersion()));