Rework the listening IP/interface selection code

Closes #11561

src/base/utils/net.h

@@ -50,6 +50,7 @@ namespace Utils
         bool isLoopbackAddress(const QHostAddress &addr);
         bool isIPInRange(const QHostAddress &addr, const QVector<Subnet> &subnets);
         QString subnetToString(const Subnet &subnet);
+        QHostAddress canonicalIPv6Addr(const QHostAddress &addr);
 
         const int MAX_SSL_FILE_SIZE = 1024 * 1024;
         QList<QSslCertificate> loadSSLCertificate(const QByteArray &data);