[appobject] introduce RegistrableObject base class (prepares #2406609)

[cwvreg] introduce lgc version 0.59 and remove unneeded method redefinition (prepares #2406609) The new logilab.common.registry makes this moot.

[BFSS] mark fs_imported value as uncachable This will finally fix the `test_bfss_fs_importing_transparency` pass again. Regression was introduced by 4ba11607d84a

[entity] add a "repo_side" parameter to `_cw_dont_cache_attribute` This parameter (defaulting to `False`) is used to inform cubicweb that we really really do not want to cache a value during creation or update. This will be used by a storage that may do very specific processing on attribute values that result in a stored value different than the provided one (e.g. BFSS `fs_importing` mode).

[merge] backport stable fixes

[entities] fix test failures introduced by fixes in workflow related message strings (completes 9bb93efa1952)

[doc/book/] Corrected typo in en/tutorials/base/customizing-the-application.rst, for the add_cubes function call

[entity,views/json] backout 353bbd17a8b6 (reopens #2559931) Calling .complete() unconditionnally from the json encoder is unsafe since on entity creation validation: * an eid may have been drawn (hence even .has_eid() would not help) while processing form data in the edit controller * a ValidationError may have been raised and the entity-creating transaction rollbacked This leads to a crash on the return path from the validation to the browser, where the json_dumps((status, args, entity)) call will stumble upon the .complete() call which will fail because the entity does not (any more) exist in the database.

[schemas] fix typo

merge with stable