Bug 20722: Display search results when searching only by ITEMTYPECAT

Bug 20722: Display search results when searching only by ITEMTYPECAT

- Create an entry for the ITEMTYPECAT authorised value category.
  Make sure to fill in the OPAC description.
- Go to administration > itemtypes and add the new category to 2 item types.
- Go to the OPAC and check that the advanced search shows your new itemtype
  group instead of the individual itemtypes.
- Check the checkbox and Search.

Signed-off-by: Mark Tompsett <mtompset@hotmail.com>
Signed-off-by: Katrin Fischer <katrin.fischer.83@web.de>
Signed-off-by: Katrin Fischer <katrin.fischer.83@web.de>
Signed-off-by: Jonathan Druart <jonathan.druart@bugs.koha-community.org>