DCKyiv 2020: Rebuild commerce workflow

[anpolimus]

1. Add sex as additional field to ticket payment.
2. Create Ticket content type with fields equal to Attendee paragraph type.
3. Migrate 2019 ticket paragraphs to Tickets nodes.
4. Configure display of Ticket node to be equal to Attendee paragraph
5. Rebuild My Tickets page (show nodes instead of order + attendee).
6. Add ability to edit tickets nodes from my tickets page.
7. Update reporting and stat to work with new Ticket ct.

[anpolimus]

8. Send QR code to tickets owners.