Change 'kill' objectives with required gear to have a field specifically with the gear UUID when appropriate

[thaddeus]

"objectives": [
            {
                "type": "kill",
                "target": "Scavs",
                "number": 12,
                "location": "Customs",
                "with": [
                    "UNTAR helmet",
                    "MF-UNTAR armor vest",
                    "Colt M4A1"
                ],
                "id": 97
            },
]

should become

"objectives": [
            {
                "type": "kill",
                "target": "Scavs",
                "number": 12,
                "location": "Customs",
                "gear": [
                    "5aa7d03ae5b5b00016327db5",
                    "5ab8e4ed86f7742d8e50c7fa",
                    "5447a9cd4bdc2dbd208b4567"
                ],
                "id": 97
            },
]

while non-item specific requirements (like situational or generic requirements like 'silenced') would remain under the 'with' field as is.

[thaddeus]

See #76 (comment) for another potential solution