Bug 29242: Flatpickr - Should autocomplete be turned off?

Bug 29242: Flatpickr - Should autocomplete be turned off?

This patch adds a step to Flatpickr initialization to add an
autocomplete attribute set to "off" so that browsers' built-in
autocomplete menus do not obscure the calendar.

To test you must be using a browser which has form history enabled.

Locate a form that includes a Flatpickr input field, e.g.  Reports
-> Catalog statistics.

Fill the date fields and submit the form. Go back to the form and click
one of the form fields you previously filled out (once in Chrome, twice
in Firefox). The browser should not show its native form history
dropdown.

Signed-off-by: David Nind <david@davidnind.com>
Signed-off-by: Katrin Fischer <katrin.fischer.83@web.de>
Signed-off-by: Jonathan Druart <jonathan.druart@bugs.koha-community.org>