[dbapi] retire repository transaction methods which were used by the dbapi
Related to #3933480.
What's new in CubicWeb 3.15?============================New functionnalities--------------------* Add Zmq server, based on the cutting edge ZMQ (http://www.zeromq.org/) socket library. This allows to access distant instance, in a similar way as Pyro.* Publish/subscribe mechanism using ZMQ for communication among cubicweb instances. The new zmq-address-sub and zmq-address-pub configuration variables define where this communication occurs. As of this release this mechanism is used for entity cache invalidation.* Improved WSGI support. While there is still some caveats, most of the code which was twisted only is now generic and allows related functionalities to work with a WSGI front-end.* Full undo/transaction support : undo of modification has eventually been implemented, and the configuration simplified (basically you activate it or not on an instance basis).* Controlling HTTP status code used is not much more easier :-`WebRequest` now has a `status_out` attribut to control the response status ;- most web-side exceptions take an optional ``status`` argument.API changes-----------* The base registry implementation has been moved to a new`logilab.common.registry` module (see #1916014). This includes code from :*`cubicweb.vreg` (the whole things that was in there)*`cw.appobject` (base selectors and all). In the process, some renaming was done:* the top level registry is now `RegistryStore` (was `VRegistry`), but that should not impact cubicweb client code ;* former selectors functions are now known as "predicate", though you still use predicates to build an object'selector ;* for consistency, the `objectify_selector` decoraror has hence be renamed to`objectify_predicate` ;* on the CubicWeb side, the `selectors` module has been renamed to`predicates`. Debugging refactoring dropped the more need for the `lltrace` decorator. There should be full backward compat with proper deprecation warnings. Notice the`yes` predicate and `objectify_predicate` decorator, as well as the`traced_selection` function should now be imported from the`logilab.common.registry` module.* All login forms are now submitted to <app_root>/login. Redirection to requested page is now handled by the login controller (it was previously handle by the session manager).*`Publisher.publish` has been renamed to `Publisher.handle_request`. This method now contains generic version of logic previously handled by Twisted. `Controller.publish` is **not** affected.Unintrusive API changes-----------------------* New 'ldapfeed' source type, designed to replace 'ldapuser' source with data-feed (i.e. copy based) source ideas.* New 'zmqrql' source type, similar to 'pyrorql' but using ømq instead of Pyro.* A new registry called `services` has appeared, where you can register server-side `cubicweb.server.Service` child classes. Their `call` method can be invoked from a web-side AppObject instance using new `self._cw.call_service` method or a server-side one using `self.session.call_service`. This is a new way to call server-side methods, much cleaner than monkey patching the Repository class, which becomes a deprecated way to perform similar tasks.* a new `ajax-func` registry now hosts all remote functions (i.e. functions callable through the `asyncRemoteExec` JS api). A convenience `ajaxfunc` decorator will let you expose your python function easily without all the appobject standard boilerplate. Backward compatibility is preserved.* the 'json' controller is now deprecated in favor of the 'ajax' one.*`WebRequest.build_url` can now take a __secure__ argument. When True cubicweb try to generate an https url.User interface changes----------------------A new 'undohistory' view expose the undoable transactions and give access to undosome of them.