Message or question list template - Add option in config file to choose severity

[freddidierRTE]

Instead of default value INFORMATION / ACTION it should be possible to set via the config file the severity of the message

Config file example :

  "messagesList": [{
        "id": "Warning",
        "title": "Warning about the state of the grid",
        "message": "A problem has been detected, please put maintenance work on hold and be on stand by",
        "question": false, 
        "severity": "ALARM"
        "recipients" : [
            "ENTITY1_FR",
            "ENTITY2_FR",
            "ENTITY4_FR",
            "ENTITY1_IT",
            "ENTITY1_NL",
            "ENTITY1_EU"
        ],
        "recipientsForInformation" : []
    },

No cypress test --> adapt unit test
Adapt documentation
Add an example in the existing example config file