Support CultureCode in GetPortalSetting and GetPortalSettings

Update stored procedures GetPortalSetting and GetPortalSettings to support culture code
What exceptions are expected here and why do you swallow them? As a module developer I'd like to handle them, for example to display an error message or fallback to different logic. Otherwise the users will get unexpected or random behaviour if the exception is intermittent. Also it seems that if there's an exception, Null.NullString will always be returned instead of defaultValue.