Read array of ethereum balances

[andrea-dintino]

We would need a statement like:

Given I read the ethereum balance for array 'ethereum_address_array'

that takes input like:

{
    "ethereum_address_array": [
        "8388f6a2a4940c3fe14d640ddf151aa771f03b81",
        "fcb3156532549730e7b118cb99a736776551f0e4",
        "6ef80725bc7eaf1e227f82dbc6c8e1f73156a438"
    ]
}

and returns an string dictionary like:

{ "8388f6a2a4940c3fe14d640ddf151aa771f03b81": {"tokens": "1000"}, "fcb3156532549730e7b118cb99a736776551f0e4": {"tokens": "1001"}, "6ef80725bc7eaf1e227f82dbc6c8e1f73156a438": {"tokens": "1002"} }