feat: finality with bls signature approach

[magnified103]

This PR introduces:

1. DRPCredentialStore (node/store/index.ts) holds the private keys and public keys for vertex signing and voting.

• DRPCredentialConfig contains the initial seed for key generation.
• DRPPublicCredential contains the public keys, base64-encoded.

export interface DRPPublicCredential {
	ed25519PublicKey: string;
	blsPublicKey: string;
}

2. FinalityState and FinalityStore (object/finality) hold the finality and voting status for hashgraph vertices.

• DEFAULT_FINALITY_THRESHOLD equals 0.51

3. BLS signature collection scheme:

• Attestation object holds a vertex hash and a signature representing a single vote.

message Attestation {
  string data = 1;
  bytes signature = 2;
}

• AggregatedAttestation contains a vertex hash, an aggregate of multiple signatures and a bitset indicating who voted.

message AggregatedAttestation {
  string data = 1;
  bytes signature = 2;
  bytes aggregation_bits = 3;
}

• ATTESTATION_UPDATE broadcast message: broadcast the attestations generated by a node upon receiving an UPDATE message.

message AttestationUpdate {
  string object_id = 1;
  repeated drp.object.v1.Attestation attestations = 2;
}

[magnified103]

Also, you forgot to update the data type in the test case for hashgraph.

fixed in 6934d13

[trungnotchung]

lgtm

[winprn]

lgtm

[hoangquocvietuet]

lgtm

[JanLewDev]

Lgtm

[anhnd350309]

lgtm

[d-roak]

lgtm