Generation error synthesis for the final user

[romaintailhurat]

⚠️ This is a stub issue, to be more thoroughly described in a near future.

If a problem happens during a questionnaire generation, most of the time the user is clueless regarding the root cause.

In the main setting (use at Insee), the generation backend for Pogues is Eno, more precisely the web service wrapper for Eno. We must provide a way to catch those generation errors and provide a clean report to the user.

It can be done:

• through the Pogues front-end directly before starting the generation process,
• after the generation process by catching a proper error message coming from the Eno API.

[romaintailhurat]

Analysis work to be done in a future sprint, see #515

[romaintailhurat]

A spec is needed, the idea is to cactch errors early, before the generation call.

[romaintailhurat]

Update: Eno Java is here, it provides a better and more precise error report. We should leverage this:

1. a first version with the raw Eno message (as a supplement to the usual generation error message in Pogues)
2. a second version with a user oriented message based on the raw Eno message

@laurentC35 @BulotF it implies devs on the back-office.

[romaintailhurat]

@romaintailhurat will provide mockup of the UI if needed

[romaintailhurat]

The UI part is ok, we are waiting for the API to be complete, see InseeFr/Pogues-Back-Office#217