Bug 14876 - Show number of holds per record on the search results

Bug 14876 - Show number of holds per record on the search results

This patch sues the existing plugin
Koha::Template::Plugin::Biblio->HoldsCount

To be consistent with current behaviour 'Holds (0)' is shown when
no holds have been placed on an item

To test:
1 - Search in staff
2 - Note holds link has no extra information
3 - Apply patch
4 - prove -v t/db_dependent/Template/Plugin/Holds.t
5 - Do search in staff that returns records with some holds (i.e. place
                some holds)
6 - Note the number of holds now displays next to the text of the link:
    Holds (#)

Signed-off-by: Barbara Johnson <barbara.johnson@bedfordtx.gov>
Signed-off-by: Jonathan Druart <jonathan.druart@biblibre.com>
Signed-off-by: Kyle M Hall <kyle@bywatersolutions.com>