Add multisignature account registration (POST)

[sridharmeganathan]

Description

Add support for multisignature registration transactions.

At this point there is no validation performed, the microservice accepts all payloads within the defined schema.

Motivation

Multisignature account registration is required as minimal functionality is available to the end-user.

Acceptance Criteria

• Multisignature registration transactions are received by the proper endpoints
• Transaction validation is applied
• Integration tests are written for the most common scenarios

Additional Information

{
  "nonce": <String>, // optional, LS takes it from the network
  "senderPublicKey": <String>,
  "moduleAssetId": <Number>,
  "asset": {
    "mandatoryKeys": [<String>],
    "optionalKeys": [<String>],
    "numberOfSignatures": <Number>,
  },
  "fee": <String>,
  "expires": <Number>, // UNIX Timestamp
  "signatures": [
    {
      "publicKey": <String>, // or address
      "signature": <String>,
    }
  ]
}

Response

{
  "data": [{
    "serviceId": <String>, // LS internal transaction ID (UUID)
    "nonce": <String>,
    "senderPublicKey": <String>,
    "asset": { ... },
    "moduleAssetId": <Number>,
    "fee": <String>,
    "expires": <Number>, // UNIX Timestamp
    "signatures": [
      {
        "publicKey": <String>,
        "address": <String>,
        "signature": <String>,
        "accountRole": <String> // mandatory/optional/owner
      }
    ]
  }],
  "meta": {
      "count": <Number>, "offset": <Number>, "total": <Number>,
  }
}