MQTT: WIP, re-organized disconnection handling, now keep track of connection status and reconnect accordingly.
This fixes bug with non-reconnecting to broker when having no published variables.
<?xml version='1.0' encoding='utf-8'?>
<SVGHMI xmlns:xsd="http://www.w3.org/2001/XMLSchema" OnWatchdog="echo Watchdog for {name} !" WatchdogInitial="10" WatchdogInterval="5" EnableWatchdog="true" Path="{name}"/>