Bug 22098: Update stocknumberAV cataloguing plugin to use objects

Bug 22098: Update stocknumberAV cataloguing plugin to use objects

This patch:
- changes SQL to Koha::AuthorisedValues
- remove type param from script tag
- fixes the plugin description

0) Do not apply the patch
1) Set the plugin
1.1) Update a biblio framework and link plugin stocknumberAV.pl to some item
subfield
1.2) Add authorised values category called "INVENTORY"
1.3) Add some authorised values: authorised value is prefix and
description is a current stock/inventory number
2) Add an item and try to use this plugin to ensure you set it
correctly
2.1) Use a defined prefix to see if the number is correct
2.2) Ensure the number is correctly incremented in authorised values
2.3) Use not defined prefix to see the error message
2.4) Insert a not prefix string (eg number) to see it is not changed
3) Apply the patch
4) Repeat 2) and see it is working the same
5) Look into patch and confirm the description does make sense and is
rigth according to what you see in UI
6) Sign off :D

Signed-off-by: Fridolin Somers <fridolin.somers@biblibre.com>
Signed-off-by: Katrin Fischer <katrin.fischer.83@web.de>
Signed-off-by: Martin Renvoize <martin.renvoize@ptfs-europe.com>