Add stellar tx fetch events cmd

[elizabethengelman]

What

Closes #2071

stellar tx fetch events --hash bffe7a918bd4d4f9ecff98829ded7a5567288eb8346ab8df761d7609502af449 --network local --output json-formatted

{
  "contract_events": [
    [
      {
        "ext": "v0",
        "contract_id": "CCFK2772GEZESMSXSWA3YN5Q6EBR6FAPGWRMHTQJZ4B5DL7BJW6CKMYA",
        "type_": "contract",
        "body": {
          "v0": {
            "topics": [
              {
                "symbol": "hello"
              },
              {
                "symbol": ""
              }
            ],
            "data": {
              "symbol": "hi"
            }
          }
        }
      }
    ]
  ],
  "diagnostic_events": [],
  "transaction_events": [
    {
      "stage": "before_all_txs",
      "event": {
        "ext": "v0",
        "contract_id": "CDMLFMKMMD7MWZP3FKUBZPVHTUEDLSX4BYGYKH4GCESXYHS3IHQ4EIG4",
        "type_": "contract",
        "body": {
          "v0": {
            "topics": [
              {
                "symbol": "fee"
              },
              {
                "address": "GBFOUPJKLSVZM2ND55AHQCVXVEAWUGO5K4XTWIV4ATYIGJ6V6EFSZVEY"
              }
            ],
            "data": {
              "i128": "52348"
            }
          }
        }
      }
    },
    {
      "stage": "after_all_txs",
      "event": {
        "ext": "v0",
        "contract_id": "CDMLFMKMMD7MWZP3FKUBZPVHTUEDLSX4BYGYKH4GCESXYHS3IHQ4EIG4",
        "type_": "contract",
        "body": {
          "v0": {
            "topics": [
              {
                "symbol": "fee"
              },
              {
                "address": "GBFOUPJKLSVZM2ND55AHQCVXVEAWUGO5K4XTWIV4ATYIGJ6V6EFSZVEY"
              }
            ],
            "data": {
              "i128": "-38852"
            }
          }
        }
      }
    }
  ]
}

Why

To allow a user to fetch all events for a given transaction

Known limitations

N/A