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'?>
<SVGHMI xmlns:xsd="http://www.w3.org/2001/XMLSchema" WatchdogInitial="10" WatchdogInterval="5" EnableWatchdog="true" Path="{name}"/>