When the tracking has its own table and a relationship to donations, the Trackings need to be persisted as their own entities:

1. Create Tracking entities with fixed IDs in tests/Fixtures/Doctrine/Tracking.php with the information from tests/Fixtures/Doctrine/Donations.php
2. Adapt the Doctrine entity creation in tests/Fixtures/Doctrine/Donations.php to use the new Tracking entities (similar to what we're doing with the Payment entities)

Leave the tracking data as a duplicate in the donation "data blob" until all code is refactored