Add support for Diceware wordlists in numbered and/or PGP-signed formats (#6791)

This allows one to directly use Diceware-compatible wordlists without having to convert the file to the plain wordlist format.

The accepted formats are described in the Diceware documentation:
https://diceware.readthedocs.io/en/stable/wordlists.html

docs/man/keepassxc-cli.1.adoc

@@ -256,6 +256,7 @@ The same password generation options as documented for the generate command can
   Sets the Path of the wordlist for the diceware generator.
   The wordlist must have > 1000 words, otherwise the program will fail.
   If the wordlist has < 4000 words a warning will be printed to STDERR.
+  Any *diceware*-compatible wordlist can used. Note however that *KeePassXC* will NOT verify the PGP signature of signed wordlists.
 
 === Export options
 *-f*, *--format*::

src/core/PassphraseGenerator.cpp

@@ -68,8 +68,28 @@ void PassphraseGenerator::setWordList(const QString& path)
     }
 
     QTextStream in(&file);
-    while (!in.atEnd()) {
-        m_wordlist.append(in.readLine());
+    QString line = in.readLine();
+    bool isSigned = line.startsWith("-----BEGIN PGP SIGNED MESSAGE-----");
+    if (isSigned) {
+        while (!line.isNull() && !line.trimmed().isEmpty()) {
+            line = in.readLine();
+        }
+    }
+    QRegExp rx("^[0-9]+(-[0-9]+)*\\s+([^\\s]+)$");
+    while (!line.isNull()) {
+        if (isSigned && line.startsWith("-----BEGIN PGP SIGNATURE-----")) {
+            break;
+        }
+        // Handle dash-escaped lines (if the wordlist is signed)
+        if (isSigned && line.startsWith("- ")) {
+            line.remove(0, 2);
+        }
+        line = line.trimmed();
+        line.replace(rx, "\\2");
+        if (!line.isEmpty()) {
+            m_wordlist.append(line);
+        }
+        line = in.readLine();
     }
 
     if (m_wordlist.size() < 4000) {