Acceptance criteria

• The export script for donations, memberships and subscriptions no longer use the spenden and request tables for querying payment data, but use the tables created in T203679: Refactor fundraising database schema instead.

Implementation Notes

• The SQL queries for this change are encapsulated in the ExportQueryBuilder classes in the DonationExport, MembershipExport and SubscriptionExport namespaces.
• The query in ExportQueryBuilder can be extended to join the payment tables.
• The query building should be changed to use Doctrine DBAL.
• We should introduce using the payment tables for getting the data.
• Create custom export fields as needed and
• Nested JSON syntax is probably different in SQLite and mysql. If so, don't unit test in SQLite.
• Add a membership application fixture using a PayPal payment.