[forms] Add autocomplete attribute for formrenderers If you set form.autocomplete = False, the form renderer in the open form tag will add the html option 'autocomplete=off'. It allows to disable the functionality of some browsers to fill in some forms automatically (for instance a profile with login/password) Closes #3747294

raise NotImplementedError("Cannot migrate such an old version. Use intermediate Cubiweb version (try 3.16.x)")