Bug 15348: Add estimated delivery date field to individual orders

Bug 15348: Add estimated delivery date field to individual orders

This patch allows you to specify an estimated delivery date per order.
The specified estimated delivery date is also considered when searching
for late orders and exporting late orders. You can also edit the
estimated delivery date from the late orders page.

Test plan:
1. Update database, rebuild schema, restart services
2. Go to Acquisitions, search for a vendor, and create a new basket
3. Add an order to the basket. When filling in the accounting details,
notice the new 'estimated delivery date' field, but don't add a date.
Save the order.
4. Confirm no date shows in the estimated delivery date column in the
orders table.
5. Modify the order. Add a date in the estimated delivery date field and
save the order.
6. Confirm the date now shows in the orders table.
7. Close the basket.
8. Go to the Late Orders page.
9. Put estimated delivery date from and to parameters in the search
filters on the left. Ensure the from and to dates encapsulate the date
you entered in the estimated delivery date field for the order.
10. Click Filter and ensure the order shows.
11. Select the checkbox next to the order. Click the Export as CSV button.
12. Open the CSV and confirm the estimated delivery date that you
entered shows as expected in the file.
13. Click Edit under the estimated delivery date. Confirm the estimated
delivery date modal pops up with the correct order line number in the
modal header.
14. Remove the estimated delivery date and click Save.
15. Confirm that the estimated delivery date calculated by Koha now
shows in the late orders table.
16. Select the checkbox next to the order. Click the Export as CSV button.
17. Open the CSV and confirm the calculated estimated delivery date
shows in the CSV.
18. Confirm tests pass: t/db_dependent/Koha/Acquisition/Order.t

Sponsored-by: Bibliotheksservice-Zentrum Baden-Württemberg (BSZ)
Signed-off-by: Christian Stelzenmüller <christian.stelzenmueller@bsz-bw.de>
Signed-off-by: Martin Renvoize <martin.renvoize@ptfs-europe.com>
Signed-off-by: Christian Stelzenmüller <christian.stelzenmueller@bsz-bw.de>
Signed-off-by: Katrin Fischer <katrin.fischer@bsz-bw.de>
Signed-off-by: Martin Renvoize <martin.renvoize@ptfs-europe.com>
Signed-off-by: Tomas Cohen Arazi <tomascohen@theke.io>