Implement Random Token based Security for POST requests

[ClundXIII]

[ClundXIII]

This will break all tests. So we need to add either an ignore option in the json config to bypass this. OR make the tests more sophisticated.

In general the token system should not affect the everyday use. Using the "Back" button in the browser and/or reloading the page with sending the same data again should still be possible within a timeframe (e.g. one day) after being forced-logout by a small cookie lifetime. Aka we will need a #9 to be implemented.