Vsite delete request form and mail

#6100 
- [x] Verify to whom we should send the mail.
- [x] Proper mail content, including links to proper URL.
- [x] Creating the overlay form, including validations.
- [x] Verify permissions for the form, and show it only as needed.
- [x] Change permissions, both default and with hook_update(), to allow site delete only to support members.
- [x] Add test to verify only support/admin can delete vsites.
- [x] Avoid validation on cancel button.
- [x] Make modal form look better.
![selection_107](https://cloud.githubusercontent.com/assets/99186/3054049/e0ebebf0-e1b2-11e3-9efd-f103803c44cb.jpeg)
- [x] Reload page after form submit in order to show drupal message.