Osng 482

This pull request contains the feature that we can deactivate user. You need to add email-properties and email-templates. A little How-To can be found here: https://github.com/osiam/addon-administration/wiki
please use the already included libraries for low-level stuff like this. guava can easily extract the stacktrace as string: `mav.addObject("stacktrace", Throwables.getStackTraceAsString(e));`