Add support deployment of scilla contracts importing user-defined libraries

[its-saeed]

Init should be like this:

    const init = [
        {
            vname: '_scilla_version',
            type: 'Uint32',
            value: '0',
        },
        {
            vname: '_extlibs',
            type: 'List(Pair String ByStr20)',
            value: [
                {
                    "constructor": "Pair",
                    "argtypes": ["String", "ByStr20"],
                    "arguments": ["AdditionLib", `${additionLibAddress}`]
                },
                {
                    "constructor": "Pair",
                    "argtypes": ["String", "ByStr20"],
                    "arguments": ["MutualLib", `${mutualLibAddress}`],
                }
            ]
        }
    ];