Acceptance criteria

• Our donation and membership entities no longer have amount, interval and payment type properties
• the tables behind these entities no longer have these columns

Implementation details

• A good starting point in the IDE is the "get usage" list for the getters and setters of these properties.
• Change the DomainToLegacyConverter and LegacyToDomainConverter classes to stop writing to the entities
• Change the fixtures to stop writing to the entities
• Remove calls to get getters for these properies from the tests and the rest of the code
• Create doctrine migrations to drop the columns.