SVGHMI: widgets are not anymore binary relative or absolute, but have a "relativeness".

Because of allowing multiple variables per widget, we must distinguish if individual variables is relative to page, not the whole widget.

<?xml version='1.0' encoding='utf-8'?>
<BeremizRoot URI_location="LOCAL://">
  <TargetType/>
  <Libraries Enable_SVGUI_Library="true" Enable_Python_Library="true"/>
</BeremizRoot>