feature: User delete option

[tillhanke]

Feature: A button under "edit profile" with the option to delete the account.

Expected behaviour: If this button is pressed the user should be set to "delete in progress" this issues mails to the financial and admin person so they can contact the user with regards to open budget. After these questions are cleared the admin should delete the person in question. Also a mail should be send to the user, with content in the style of: "your account will be deleted shortly if you don't get any information within the next 4 weeks please contact the administrator (email)"

I think this can be connected to #550