Bug 5287: Add floating toolbar to search results in OPAC

Bug 5287: Add floating toolbar to search results in OPAC

This patch adds the "hc-sticky" JavaScript library to the OPAC and uses
it to make the search results toolbar "stick" to the top of the page as
the user scrolls down.

This patch also moves search results pagination into the toolbar so that
pagination links are available. Font Awesome icons are added to the
pagination include to replace arrow HTML entities.

To test, apply the patch and rebuild the OPAC CSS
(https://wiki.koha-community.org/wiki/Working_with_SCSS_in_the_OPAC_and_staff_client).

 - Perform a catalog search in the OPAC which will return multiple pages
   of results. Confirm that the toolbar "sticks" and that all controls
   in the toolbar work correctly.
 - Test at various browser widths to confirm that it adapt well to
   various sizes.

Signed-off-by: Liz Rea <wizzyrea@gmail.com>
Signed-off-by: Katrin Fischer <katrin.fischer.83@web.de>
Signed-off-by: Martin Renvoize <martin.renvoize@ptfs-europe.com>