Until now, portal_sessions was only reliably usable when using a family with only one zope node, because the session data was using RAM cache.
When used by authenticated users it was more or less usable, because of haproxy
sticky cookie that we set for authenticated users, but for non authenticated users
this was basically unusable.
This was especially a problem for CaptchaField, for which users are generally not
authenticated.

This changes portal_sessions to use a distributed cache, which brings several
differences:
 - sessions are now shared between all zopes of a cluster.
 - storing ERP5 temp documents is still possible, but modifying a temp document in
   session does not automatically save the changes in session, for next session read
   to be using the modified document it's required to save the document explicitly.
 - session respects transaction semantics, changes are only persisted in session when transaction commits successfully.
 - `portal_caches.clearAllCaches` API no longer clear all sessions.

See merge request !1451

See merge request nexedi/erp5!1466

See merge request !1464

book_signature_list, book_version_list, book_distribution_list are not done and always empty

easy to read

Since 9f6178cb (product: Add Web Illustration to the seperately exported
property dict, 2021-06-23) the export format is different.

CodingStyle detects this and report it as a failure, so re-exporting is
required for the test.

For consistency with default ERP5JS and because it's convinient to have the
jump here, to access the document tab that is now a jump action.

See merge request !1454

See merge request !1365

See merge request nexedi/erp5!1453