Bug 24606: Implement item templates

Bug 24606: Implement item templates

This patch set implements item editor templates for community Koha.

Test Plan:
1) Apply this patch set
2) Run updatedatabase.pl
3) Restart all the things!
4) prove t/db_dependent/Koha/Item/Template*
5) As a non superlibrarian, enter the item editor
6) Set some item fields, save as a new template using the buttom and
   form below the editor.
7) Test loading a template without remembering for the session
8) Test loading a template while remembering for the session
9) Test deleting a template
10) Test updating a template
11) Create one or more shared templates
12) Log in as another non superlibrarian without the new permission manage_item_editor_templates,
    verify you cannot edit/delete templates shared to you
13) Enable the new permission manage_item_editor_templates,
    verify you can now edit and delete templates shared to you

Signed-off-by: David Nind <david@davidnind.com>
Signed-off-by: Katrin Fischer <katrin.fischer.83@web.de>
Signed-off-by: Tomas Cohen Arazi <tomascohen@theke.io>