Bug 29002: Prevent booking a checked out item

Bug 29002: Prevent booking a checked out item

This patch updates the bookings logic to prevent placing a booking
on an item that is checked out to start prior to it's due date.

Test plan
1) Follow the previous test plans
2) Add a checkout of an item
3) Attempt to place a booking and note that the item is not available to
   be booked until after it's due date.

Signed-off-by: Martin Renvoize <martin.renvoize@ptfs-europe.com>
Signed-off-by: Janet McGowan <janet.mcgowan@ptfs-europe.com>
Signed-off-by: Caroline Cyr La Rose <caroline.cyr-la-rose@inlibro.com>
Signed-off-by: Laurence Rault <laurence.rault@biblibre.com>
Signed-off-by: Kyle M Hall <kyle@bywatersolutions.com>
Signed-off-by: Tomas Cohen Arazi <tomascohen@theke.io>