Add AdditionalMediaInfo fields

[bakercp]

e.g.

[warning] AdditionalMediaInfo::fromJson: Unknown key: description : ""
[warning] AdditionalMediaInfo::fromJson: Unknown key: embeddable : true
[warning] AdditionalMediaInfo::fromJson: Unknown key: title : ""
[warning] AdditionalMediaInfo::fromJson: Unknown key: call_to_actions : {
    "watch_now": {
        "url": "https://live.en-marche.fr"
    }
}

[warning] User::fromJSON: Unknown key: withheld_in_countries
[
    "TR"
]