Thalia Pay: Export financial information that can be imported to Conscribo

One-sentence description

Export financial information that can be imported to Conscribo

Motivation

Because we want to introduce Thalia Pay (#632)

Desired functionality

Have an option to export financial payment information that can be imported in Conscribo. We currently have an export option but the use format cannot be used with Conscribo. If we add the format Conscribo wants the work to process direct debits (which might be a lot) will be decreased a lot.

Suggested implementation

• Need to determine the format with the treasurer.
• We can do this by adding extra payment actions to the payments.