Bug 16524: Use floating toolbar on item search

Bug 16524: Use floating toolbar on item search

To test:
1) Go to item search
2) Confirm toolbar at top of page with Search button, goes down page as
   you scroll
3) Confirm search button has been removed from final output fieldset
4) Confirm everything works as expected

Sponsored-by: Catalyst IT
Signed-off-by: Owen Leonard <oleonard@myacpl.org>
Signed-off-by: Jonathan Druart <jonathan.druart@bugs.koha-community.org>
Signed-off-by: Brendan Gallagher <brendan@bywatersolutions.com>
(cherry picked from commit 2afff4e8502d724f4f9e46bd406e1f00263b2b21)
Signed-off-by: Frédéric Demians <f.demians@tamil.fr>