cmake: bump min version 3.5 -> 3.10 to avoid warning with cmake 31.1;

also add min version to all CMakeLists.txt
GUI: add missing accelerator to UPCA/UPCEAN.ui "Guard Whitespace";
  add default value to some "Default" buttons;
  reformat DAFT examples again; add \^@ to special escs hint

frontend_qt/CMakeLists.txt

@@ -3,6 +3,7 @@
 # SPDX-License-Identifier: GPL-3.0-or-later
 # vim: set ts=4 sw=4 et :
 
+cmake_minimum_required(VERSION 3.10)
 project(zint-qt)
 
 set(CMAKE_AUTORCC ON)