Bug 35469: Add 'manage_bookings' permission to biblios/checkouts

Bug 35469: Add 'manage_bookings' permission to biblios/checkouts

This patch adds the manage_bookings subpermission check to the
biblios/{biblio_id}/checkouts endpoint and updates the corresponding
unit test too.

Signed-off-by: Nick Clemens <nick@bywatersolutions.com>
Signed-off-by: Marcel de Rooy <m.de.rooy@rijksmuseum.nl>
Signed-off-by: Katrin Fischer <katrin.fischer@bsz-bw.de>
(cherry picked from commit 5e0afb772a4a2b100ee14c1da0c323fcc32d0fb2)
Signed-off-by: Fridolin Somers <fridolin.somers@biblibre.com>