Added index idx_published_ordering to language table

In this pull request I have added an index for the language table to improve the performance of this query

SELECT *
  FROM #__languages
  WHERE published=1
  ORDER BY ordering ASC

To improve readability of code, please use,

```
<?php

$query = $db->getQuery(true)
->select(
	array(
		'lang_id',
		'lang_code',
		'title',
		'title_native',
		'sef',
		'image',
		'description',
		'metakey',
		'metadesc',
                
	)
);
```