Name (add semantic indexes) for rows and columns for translation node overview table so other modules can alter content.

Right now there are too many modules overriding the full tab just because the table data has no proper indexes. If it had then the modules wouldn't need to menu_alter() and override the whole tab and they could just use hook_page_alter().

The problem with many modules overriding the same tab is that they end up clashing as all of them try to menu_alter the same tab, and making them compatible requires some complex logic.

Some of the modules are Internationalization, Entity Translation, Translation overview, TMGMT, etc..

This patch just adds proper indexes for rows, and columns so the table looks just the same, but other modules can actually alter that data. It would be a great help for people working on 'multilingual' modules while changing basically nothing on Drupal core.