[session] deprecate `hijack_user` method
The semantic of this method is wicked and lead to very hard violation of sanity.
(multiple transaction using the very same cursors). We deprecated the API to be
able to drop it as soon as possible.
The method was added long ago for some notification trick. It is not needed
since we sent notification on ``postcommit_event``.
(closes #2781782)
What's new in CubicWeb 3.17?
============================
New functionalities
--------------------
* add a command to compare db schema and file system schema
(see `#464991 <http://www.cubicweb.org/464991>`_)
* Add CubicWebRequestBase.content with the content of the HTTP request (see #2742453)
(see `#2742453 <http://www.cubicweb.org/2742453>`_)
* Add directive bookmark to ReST rendering
(see `#2545595 <http://www.cubicweb.org/ticket/2545595>`_)
API changes
-----------
* drop typed_eid() in favour of int() (see `#2742462 <http://www.cubicweb.org/2742462>`_)
* The SIOC views and adapters have been removed from CubicWeb and moved to the
`sioc` cube.
* The web page embedding views and adapters have been removed from CubicWeb and
moved to the `embed` cube.
* The email sending views and controllers have been removed from CubicWeb and
moved to the `massmailing` cube.
* ``RenderAndSendNotificationView`` is deprecated in favor of
``ActualNotificationOp`` the new operation use the more efficient *data*
idiom.
* Looping task can now have a interval <= ``0``. Negative interval disable the
looping task entirely.
Deprecation
---------------------
* ``ldapuser`` have been deprecated. It'll be fully dropped in the next
version. If you are still using ldapuser switch to ``ldapfeed`` **NOW**!
* ``hijack_user`` have been deprecated. It will be dropped soon.
Deprecated Code Drops
----------------------
* The progress views and adapters have been removed from CubicWeb. These
classes were deprecated since 3.14.0. They are still available in the
`iprogress` cube.
* API deprecated since 3.7 have been dropped.