Compliant with Hyperledger Sawtooth Consensus API

[therealdannzor]

From https://github.com/hyperledger/sawtooth-rfcs/blob/main/text/0004-consensus-api.md:

Block {
    Id: string               // This block's identifier
    Previous Id: string      // This block's parent's identifier
    Index: unsigned integer  // The "height" of this block
    Consensus: bytes         // The opaque consensus payload for this block
    Signer: bytes            // The signer of this block
    Summary: bytes           // A digest of the contents of the block
}