Backport executable finder to allow use of local npm package binaries
I dont want to know how this could have work before
Merge pull request #955 from romainneutron/executable-finder-backport

[3.8] Backport executable finder to allow use of local npm package binaries
Merge branch '3.8'

Conflicts:
	lib/Alchemy/Phrasea/Core/CLIProvider/CLIDriversServiceProvider.php
	tests/Alchemy/Tests/Phrasea/Controller/SetupTest.php
Add dependency on Ratchet and react ZMQ
Add check on libevent for production
Remove signal listener once a signal has been caught
Add task manager broadcaster subscriber
Minimal fix for callback declaration
Add Websocket server
Add WebsocketServer command
Add patch to version 3.9.0-alpha.11
Bump to version 3.9.0-alpha.11
Add useful infos in session storage
Add authorization strategy for WAMP topics
Address PR comments