Bug 19249: Fix date inputs on patron quick add form

Bug 19249: Fix date inputs on patron quick add form

This patch create a "apply_flatpickr" JS function to make the code
reusable from the template, where we loop over the date inputs to
reinstantiate flatpickr.

Signed-off-by: Sally <sally.healey@cheshiresharedservices.gov.uk>
Signed-off-by: Nick Clemens <nick@bywatersolutions.com>
Signed-off-by: Tomas Cohen Arazi <tomascohen@theke.io>
(cherry picked from commit 28dc7f1f02b0515648b76abd71eaa142f5f52396)
Signed-off-by: Martin Renvoize <martin.renvoize@ptfs-europe.com>