Bug 29240: Centralise from/to handling

Bug 29240: Centralise from/to handling

This patch moves to using a data-start_for attribute to point the 'from'
flatpickr to the 'to' flatpickr.

We also fix the date validation issue in the onClose handler inline.

Test plan.
1. Check that the from/to datpicker combinations work on each of the
   changed pages.
2. Look at the console for errors, there should be none

Signed-off-by: Owen Leonard <oleonard@myacpl.org>
Signed-off-by: Martin Renvoize <martin.renvoize@ptfs-europe.com>
Signed-off-by: Jonathan Druart <jonathan.druart@bugs.koha-community.org>