Bug 29459: Replace some missed datetimepickers in circulation templates with Flatpickr

Bug 29459: Replace some missed datetimepickers in circulation templates with Flatpickr

This patch updates a few more instances of jQueryUI datepickers which
were missed initially, replacing them with Flatpickr widgets.

Also changed: A few datetime input fields are updated to have a size of
20, consistent with other datetime input fields.

To test, apply the patch and go to Circulation.

Check in:

- With the 'SpecifyReturnDate' system preference enabled, go to Check
  in.
- Click the "Checkin settings" link.
- Test the "Specify return date" field. Clicking it should trigger a
  Flatpickr widget with a time picker. It should limit your selection to
  dates in the past.
- Check the "Remember return date" checkbox and confirm that the date is
  preserved over page reloads.
- Check and uncheck the "Box drop mode" checkbox to confirm that the
  return date field is disabled and enabled correctly.

Check out:

- With the 'AllowRenewalOnHoldOverride' preference enabled, check out to
  a patron who has a checkout which is on hold for another patron.
- At the bottom of the table of checkouts, click the "Override renewal
  restrictions" checkbox.
- The on-hold checkouts should now have a checkbox in the "Renew"
  column. Check one or more of these checkboxes.
- In the table footer you should now see two date inputs, "Renewal due
  date" and "On hold due date." These should both trigger Flatpickr
  widgets with time pickers.
- Confirm that your date selections are submitted correctly when you
  renew items.

ILL checkout:

- Create a new ILL request with the type "book," filling in at least
  title, patron, and destination library.
- On the "Manage ILL request" page, click "Confirm request" and "Confirm
  request" on the next confirmation page.
- There should now be a "Check out" button in the "Manage ILL request"
  toolbar. Click it.
- Test the "Due date" field. It should trigger a Flatpickr widget with a
  time picker.

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