ownership proof api

[0xbok]

the ownership proofs are fetched from the continuously updating merkle tree, so this doesn't reflect their finalized proofs. We should have another endpoint to get finalized ownership proof.

query {
  getOwnershipProofs(
    address:[218, 30, 169, 125, 76, 109, 114, 49, 37, 178, 110, 74, 20, 65, 195, 153, 208, 234, 11, 228]) {
      index,
    lowCoin,
    highCoin
  }
}

{
  "data": {
    "getOwnershipProofs": [
      {
        "index": 1,
        "lowCoin": 0,
        "highCoin": 5
      }
    ]
  }
}