Allow processing data before writing

[caiquecastro]

Allow processing data, the source fetched data would be processed before writing to destionation.

{
    "destination": {
        //...
    },
    "source": {
        //...
    },
    "process": {
        "id": {
            "transformation": "uuidGenerate"
        },
        "admission": {
            "transformation": "dateFormat",
            "parameters": {
                "format": "DD/MM/YYYY"
            }
        },
        "approverId": {
            "transformation": "nullIfEmpty"
        }
    }
}