Add DataTables buttons and select extensions to replace retired TableTools

Hah! Yeah. What a funny left over. :-) Thanks for the finding @Anybody! Great work, as always.

It starts from line 152 - 156 in datatable.module file of 2.x dev

  // Enable TableTools plugin support, if necessary.
  if (isset($options['elements']['table_tools']) && $options['elements']['table_tools']) {
    $datatable_options['oTableTools'] = [
      'sSwfPath' => base_path() . 'libraries/datatables/extras/TableTools/media/swf/copy_csv_xls_pdf.swf',
    ];

The if statement shows me that there used to be an option form element for datatable settings? And since $options['elements']['table_tools'] seems not be left in somewhere else (at least I cannot find it in 2.x-dev on a quick glimpse) it seems to be a leftover from the option setting removal? All I found was when this feature has been added I think here: https://www.drupal.org/project/datatables/issues/1029798 → -- Would be great if someone can point me to the issue where it has been removed again so we can make sure that we do not overlook sth here.

PS: Edited the title for better patch readability and the OT for better issue following ;-) No need to keep all the headlines in it.

About this see also 📌 Possible Releaseblocker for Drupal DataTables v3 (^10|^11) Active

A related issue 🐛 Notice: Undefined index: table_tools in /datatables/src/Plugin/views/style/DataTables.php on line 121 Postponed: needs info .

After rethinking this issue I think it needs sharpening. As the OT already quoted from here: https://datatables.net/extensions/tabletools/ we need to replace TableTools with the now supported buttons and select elements. Change title repectively.