Merge branch '3.1.x' into 3.2.x
* 3.1.x:
[ticket/14789] Add form tokens to tests and uncomment add_form_key
[ticket/14789] Add link hashes and form tokens to all acp links/buttons
Merge pull request #4452 from marc1706/ticket/14789
[ticket/14789] Further harden ACP link and form checks
* marc1706/ticket/14789:
[ticket/14789] Add form tokens to tests and uncomment add_form_key
[ticket/14789] Add link hashes and form tokens to all acp links/buttons
[ticket/14789] Add link hashes and form tokens to all acp links/buttons
This will further harden the ACP security by adding link hashes to links and
form tokens to forms that did not have these yet and result in modified
settings or write action on the filesystem or database. These few links and
forms were still relying on the global ACP protection, mainly due to them
not posing further risks of compromising data. After this change these will
now also be properly protected against tampering.
