SVGHMI: preliminary implementation of a general enable bit for all widgets, using "#" at the end of widget declaration, and a "disabled" element that becomes visible instead of widget when disabled.

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