Some change to imporve reminder mail usability:
1. Scheduled date on POL of the PO form now is always editable.
2. Improve tooltip for the reminder email
3. don't show number of days when reminder email not checked on
both PO and partner form.
4. only show "confirm receipt date" button in debug model
5. In the mail, format date by partner.lang
6. Add button to send preview reminder mail
7. On default, receipt_reminder_email on res.partner is False
8. merge expected_date with date_planned (done by FP)
Task 2265912
PR #52693
Fabien Pinckaers
ccfc54113d