[api] Get broadcast tx many-outputs

[GET] /api/transactions/broadcast/many-outputs/{operationId}

See `[GET] /api/capabilities`

Should return broadcasted transaction by operation ID . All transactions with many
outputs, that were broadcasted by the ` [POST] /api/transactions/broadcast` should be available here.

Response:

```js
{
// Operation ID.
“operationId”: “guid”,
// State of the transaction
// enum values:
//
// - inProgress : transaction is being in-progress
// - completed : transaction is completed for sure. When
// transaction is switched to the completed state,
// amount of this transaction should be already subtracted from
// the balance returned by the [GET] /api/balances ,
// for outgoing transactions
// - failed : transaction is failed
“state”: “enum”,
// Transaction moment as ISO 8601 in UTC
“timestamp”: “datetime”,
// Source address
“fromAddress”: “string”,
// Destinations.
// Should be non null if the state is Completed.
“outputs”: [
{
// Destination address
“toAddress”: “string”,
// Actual amount that is transferred to the
// toAddress . Integer as string, aligned
// to the asset accuracy. Actual value can be
// calculated as
// x = amount / (10 ^ asset.Accuracy)
“amount”: “string”
} ],
// Fee. Is integer as string, aligned
// to the asset accuracy. Actual value can be
// calculated as
// x = sourceFee * (10 ^ asset.Accuracy)
// Should be non empty if the state is Completed
“fee”: “string”,
// Transaction hash as base64 string.
// Can be empty
// Should be non empty if the state is Completed
“hash”: “string”,
// Error description
// Can be empty
// Should be non empty if the state is Error
“error”: “string”,
// Error code.
// Can be empty.
// Should be non empty if the state is Failed.
// enum values:
// - unknown : any error that does not fit another codes.
// - amountIsTooSmall : amount is too small to execute
// transaction
// - notEnoughBalance : transaction can’t be executed due
// to balance insufficiency on the source address.
// Should be non empty if the state is Error
“errorCode”: “enum”,
// Incremental ID of the moment, when the transaction
// state changing is detected. It should be the same
// sequence as for block in the [GET] /api/balances
// response. In other words block number/height.
“block”: integer64
}
```

Errors:

* `204 No content` - specified transaction not found