SVGHMI: i18n: ensure langs always appea in same order, and add two variables that are updated automatically when selecting a new language : lang_name and lang_code. Also fixed i18n startup, prevent wrong lang numer to crash loading.

<?xml version='1.0' encoding='utf-8'?>
<BaseParams xmlns:xsd="http://www.w3.org/2001/XMLSchema" IEC_Channel="2" Name="py_ext_0"/>