Bug 21216: Add filter/search options to notices table

Bug 21216: Add filter/search options to notices table

This patch adds a DataTables toolbar to the Notices & slips table,
including a filter field, column visibility, and data export options.

To test, apply the patch and clear your browser cache if necessary.

 - Go to Tools -> Notices & slips
 - Confirm that there is a table toolbar with a filter, a "Column
   visibility" button, and "Excel," "CSV," "Copy," and "Print" buttons.
 - Confirm that showing and hiding columns via the button is working
   correctly.
 - Confirm that only the first four columns are sortable.

Go to Administration -> Columns settings.

- Expand the "Tools" section.
- Find "id=lettert."
- Make some selections to configure default settings of the reports
  table.
- Return to reports and confirm that these defaults are applied.

Signed-off-by: Claire Gravely <claire.gravely@bsz-bw.de>
Signed-off-by: Michal Denar <black23@gmail.com>
Signed-off-by: Michal Denar <black23@gmail.com>
Signed-off-by: Katrin Fischer <katrin.fischer.83@web.de>
Signed-off-by: Nick Clemens <nick@bywatersolutions.com>