Bug 14828: Use Koha::ItemType[s] everywhere C4::ItemType was used

Bug 14828: Use Koha::ItemType[s] everywhere C4::ItemType was used

This patch mainly replaces C4::ItemType->all with
Koha::ItemTypes->search.

Test plan:
At the places where the C4::ItemType module was used, confirm there is
no regression:
- acqui/neworderempty.pl
- catalogue/itemsearch.pl
- admin/item_circulation_alerts.pl
and the 2 cataloguing plugins:
- marc21_linking_section.pl
- unimarc_field_4XX.pl

QA step:
prove t/db_dependent/HoldsQueue.t should return green
Note that the tests were buggy.

Signed-off-by: Marc Véron <veron@veron.ch>
Signed-off-by: Kyle M Hall <kyle@bywatersolutions.com>
Signed-off-by: Brendan Gallagher brendan@bywatersolutions.com