The new Linebourse's website uses new requests to an API that are implemented
in a brand new browser class (LinebourseAPIBrowser).
Caisse d'Epargne's connections still use the old Linebourse website,
that's why an additional class attribute stores the browser to use
It is only used by Credit cooperatif's connections so far, so the
existing code has to be kept as such, using if-conditionals on the
current url to choose which requests to run.
Also, raise an ActionNeeded for the first connection (CGUs)