Thalia Pay: Add user-instructions for activating in bankaccounts

Job Doesburg
2019-11-03T20:34:15+01:00

Add information about Thalia Pay to bankaccounts

### Motivation

People should know what Thalia Pay is and how to activate it.

### Desired functionality

Something about that if you sign a direct debit, it will be used for Thalia Pay etc.

### Suggested implementation

Maybe ask the board? Or just come up with something ourselves. It should not be too extensive in my opinion, just something short.