[workflow view] Display a non-localized version of state/transition names (closes #1912537).

[repo] Add a publish/subscribe mechanism for inter-instance communication using zmq Each repo can have a publishing and any number of subscribing sockets whose addresses are specified in the instance's configuration. An application or cube can subscribe to some 'topics', and give a callback that gets called when a message matching that topic is received. As a proof of concept, this introduces a hook to clean up the caches associated with the repository when an entity is deleted. A subscription is added using Repository::zmq::add_subscription; the callback receives a list representing the received multi-part message as argument (the first element of the message is its topic).

[migration] fire hooks in postcreate by default (closes #1417110) also turn usage of hooks_control to relevent session's method

[migration] `add_relation_type` warns and add missing definitions on already existing rtypes (closes #2121979)

[i18n] fix translations of login actions in french (closes #1546397)

([config] add file encoding information to python files (closes #1942655)

[primary view] delete PrimaryView.skip_none attribute (closes #2093250) it was already broken anyway, since introduction of reledit (a while ago)

[entities system table] change asource and source column size (closes #1951819)

[view] fix error messages of NotImplementedError

kill dead code in Workflow view This looks like it's been missed in r5224:34e669b6fd95.