Implements hook_system_info_alter().
The Content Translation module is deprecated in Drupal 8 in favor of the Entity Translation and is planned for removal. Until an upgrade path is available, it will still be possible to enable it, if necessary, through the module API or by tweaking the system module list configuration by hand. Morever every D8 site where Content Translation is installed (not necessarily enabled) will still be able to see it as usual in the module page.
function node_system_info_alter(&$info, $file, $type) {
if ($type == 'module' && $file->name == 'translation') {
$info['hidden'] = !module_exists('translation') && config('system.module.disabled')
->get('translation') === NULL;
}
}