feat: json metadata checker.

[matiwinnetou]

Putting transactions on chain without some sanity check is spooky, let's run the code via json metadata checker.

{
  "metadata": {
    "creation_slot": "10278",
    "version": "1.0"
  },
  "org": {
    "country_code": "CH",
    "name": "Cardano Foundation",
    "tax_id_number": "CHE-184477354",
    "id": "75f95560c1d883ee7628993da5adf725a5d97a13929fd4f477be0faf5020ca94",
    "currency_id": "ISO_4217:CHF"
  },
  "txs": [
    {
      "date": "2023-10-03",
      "number": "TRANSFER3",
      "batch_id": "2c45663f4ab1b7b709ecdf9a6376f9caf0ebce5ebe21a4917519f1af24dd4852",
      "id": "48335c2b63cffcef2a3cd0678b65c4fb16420f51110033024209957fbd58ec4e",
      "type": "Transfer",
      "items": [
        {
          "amount": "2000000.00",
          "event_code": {
            "code": "99001100",
            "name": "Payment to Transit Clearing"
          },
          "project": {
            "cust_code": "AN 000002 2023",
            "name": "Accounting Ledger on the Blockchain"
          },
          "cost_center": {
            "cust_code": "3000",
            "name": "Operations"
          },
          "document": {
            "number": "TRX-0003",
            "vat": {
                "cust_code": "CH-VH-3.8",
                "rate": "3.8"
            },
            "currency": {
              "cust_code": "USD",
              "id": "ISO_4217:USD"
            },
            "counterparty": {
                "cust_code": "test_vendor1",
                "type": "VENDOR"
            }
          },
          "id": "9c6e241e1136e20e3b5033861156a1e453dce463575ebbebaa813e2af73fa95c",
          "fx_rate": "0.91277"
        }
      ],
      "accounting_period": "2023-10"
    },
    {
      "date": "2023-10-09",
      "number": "TRANSFER5",
      "batch_id": "2c45663f4ab1b7b709ecdf9a6376f9caf0ebce5ebe21a4917519f1af24dd4852",
      "id": "012ae0309054b03a3bd2d3dee3741d88a89b6ea55cadb9da7f7e9c6158eaf93a",
      "type": "Transfer",
      "items": [
        {
          "amount": "1000000.00",
          "event_code": {
            "code": "11001100",
            "name": "Bank Transfer"
          },
          "document": {
            "number": "TRX-0005",
            "currency": {
              "cust_code": "ADA",
              "id": "ISO_24165:ADA"
            }
          },
          "id": "f0fc7b88b6288bdd248f9db932c6a14ea7d28cef234d11ae91ca07f9bfa3c440",
          "fx_rate": "0.85805"
        }
      ],
      "accounting_period": "2023-10"
    }
  ]
}