mailman -- CSRF hardening in parts of the web interface

The late Tokio Kikuchi reported:

We may have to set lifetime for input forms because of recent
activities on cross-site request forgery (CSRF). The form lifetime
is successfully deployed in frameworks like web.py or plone etc.
Proposed branch lp:~tkikuchi/mailman/form-lifetime implement
lifetime in admin, admindb, options and edithtml interfaces.
[…]

The web admin interface has been hardened against CSRF attacks by
adding a hidden, encrypted token with a time stamp to form submissions
and not accepting authentication by cookie if the token is missing,
invalid or older than the new mm_cfg.py setting FORM_LIFETIME which
defaults to one hour. Posthumous thanks go to Tokio Kikuchi for this implementation […].