Feature/oneof block

[kamilsa]

Description of the Change

Before it was:

message Block {
  // block_v1 fields
}

From now on it will be

message Block_v1 {
// block_v1 fields
}

message Block {
  oneof block_version {
    Block_v1 block_v1 = 1;
  }
}

Such changes would allow us to introduce Block_v2 and further versions, by simply adding them to oneof in Block message. Internally we will be able to recognize and manage different version of the blocks.

Benefits

Iroha will be able to process different versions of the blocks.

Possible Drawbacks

Format of genesis block is changing. So if you used old iroha, you will not be able to use old block store

[Warchant]

Another drawback is legacy for new networks :(

[muratovv]

Maybe stay just version here?

[MBoldyrev]

I suggest not removing this include, even if it works without it, because we directly create and use rapidjson::Document in this file.

[MBoldyrev]

Suggested change

	logger->error("error while parsing serializing genesis block");
	logger->error("error while parsing serialized genesis block: " + error.error);