Add password reset facility

[kennygrant]

Need link for password reset, plug in mail account to send mails for this.

[msiebuhr]

When trying to register with an existing email (I forgot i already signed up), i get

This email is already in use, please send a password reminder.

But there's no password reset functionality to be found on the page (there seem to be hints in the source that /users/password/reset or so should work, but nothing of the sort works on the site).