Add switch for KF5 (QT6) and Mod Cmake

if we want to test QET on QT6, KF5 must be removed from the code,
this switch is for that,

this is for testing only

tests/catch/CMakeLists.txt

@@ -88,15 +88,8 @@ target_link_libraries(
     PUBLIC
     Catch2::Catch2
     PRIVATE
-    KF5::WidgetsAddons
-    KF5::CoreAddons
-    Qt::Gui
-    Qt::Xml
-    Qt::Svg
-    Qt::Sql
-    Qt::Network
-    Qt::Widgets
-    Qt::Concurrent)
+    ${KF5_PRIVATE_LIBRARIES}
+    ${QET_PRIVATE_LIBRARIES})
 
 if (DEFINED ENV{CATCH_INCLUDE_DIR})
     set(CATCH_INCLUDE_DIR $ENV{CATCH_INCLUDE_DIR})