Bug 21946: Display parent-child relationship on smart-rules.pl

Bug 21946: Display parent-child relationship on smart-rules.pl

To test:
 1 - Set some itemtypes to have a parent
 2 - Browse to Administration -> Circulation and fines rules
 3 - Note new description of parent/child relationships at top of page
 4 - Note that itemtype dropdown for circ rules shows child types under parents
 5 - Set a rule for a child type
 6 - Note it displays as Parent->Child
 7 - Have three child types under a parent
 8 - Set the parent 'Current checkouts allowed' to 3
 9 - Set the children 'Current checkouts allowed' to:
     type1 = 2
     type2 = 1
     type3 = 1
10 - Create some items of the type above
11 - Note you can checkout 2 of type 1, and not 3
12 - Note you can checkout 1 of type 2, but not 2
13 - Note that you now cannot checkout any of type3
14 - Note you cannot checkout any of the parent type
15 - Return one of the other items and note you can now checkout an item of type3
16 - Return another item and note you can checkout an item of the parent type
17 - Return all
18 - Set the parent type to 1
19 - Now note you can only checkout 1 of any of the children
20 - Set the parent to 0
21 - Note you cannot checkout any of the child types

Signed-off-by: Liz Rea <wizzyrea@gmail.com>
Signed-off-by: Lisette Scheer <lisetteslatah@gmail.com>
Signed-off-by: Alex Arnaud <alex.arnaud@biblibre.com>
Signed-off-by: Jonathan Druart <jonathan.druart@bugs.koha-community.org>