Acceptance criteria:

• Entities no longer contain payment objects, just a payment ID
• There is a migration script to create payment objects for existing memberships

Running the migration is not part of this ticket.

Implementation notes:

• Create a migration for the request table and "MembershipApplication" entity:
  • Remove the payment property from membership domain and doctrine entity
  • Add paymentId property to membership domain and doctrine entity. We won't interact directly with payment entities from the membership bounded context, only through payment use cases
  • Remove the paymentBankAccountHolder field
  • Create new payments from the contents of the data blob

If you run into mapping trouble, you might want to register the custom data types from payment on your migration script (see PaymentContextFactory)