Vertaal automatische mailtjes aan het bestuur

Ghost User
2017-12-10T21:13:08+01:00

Emails to the board should be in English as well.

### Why?

The board might some day be non-Dutch.

### Current implementation

The emails were copied from concrete5, so are still Dutch. They were added in !502 and others.

### Desired implementation

The emails should be in English.