Include email, phone number in Event registrations overview

Thom Wiggers
2018-03-28T20:34:41+02:00

Currently, you can get this information through the export. It'd be convenient to also have an email link, and a phone number.

### Desired behaviour

![image](/uploads/4252264171ada10f3f95c1e3f0591d57/image.png)

Don't display everything inline, because a) it makes the tables unwieldy, and b) it may result in data leaks.