SVGHMI: split page switch into switching subscription and switching elements in the DOM, to ensure that subscriptions have been send before changing DOM, and avoid some flicker.
<?xml version='1.0' encoding='utf-8'?>
<BeremizRoot URI_location="LOCAL://">
<TargetType/>
<Libraries Enable_SVGUI_Library="true" Enable_Python_Library="true"/>
</BeremizRoot>