Build Merkle Patricia Proof generator tool

[benjaminbollen]

Code exists but needs to be brought up to date.

Tool should query gateway for first and second (and all) nonce.

Once merged use the tool to regenerate test #698 and #700

[abhayks1]

Branch for reference: https://github.com/sarvesh-ost/mosaic-contracts/tree/eth_get_proof_utility