SVGHMI: Add support for forcing widget update frequency with period longer than a second. As an example, "HMI:Display|10s@/myvar" updates variable every 10 seconds.

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