[proto] Unnecessery protobuf messages

[liran-funaro]

Some of the protobuf messages can be removed to reduce the number of protobuf messages.
This can improve the API's readability.

For example:

VC

message Tx {
  protocoordinatorservice.TxRef ref = 1;
  repeated protoblocktx.TxNamespace namespaces = 2;
  optional InvalidTxStatus prelim_invalid_tx_status = 3;
}

message InvalidTxStatus {
    protoblocktx.Status code = 1;
}

Can be reduced to:

message Tx {
  protocoordinatorservice.TxRef ref = 1;
  repeated protoblocktx.TxNamespace namespaces = 2;
  optional protoblocktx.Status prelim_invalid_tx_status = 3;
}

Notify

message NotificationResponse {
    repeated TxStatusEvent tx_status_events = 1;
    repeated string timeout_tx_ids = 2;
}

message TxStatusEvent {
    string tx_id = 1;
    protoblocktx.StatusWithHeight status_with_height = 2;
}

Can be reduced to:

message NotificationResponse {
    repeated protoblocktx.TransactionsStatus tx_status_events = 1;
    repeated string timeout_tx_ids = 2;
}

Moreover, protoblocktx.TransactionsStatus and protoblocktx.StatusWithHeight can be removed completely by using protoblocktx.TxStatusInfo.

[liran-funaro]

@cendhu commented in #110 on additional duplications.

• protosigverifierservice.Tx and protocoordinatorservice.Tx are duplicates.
• protosigverifierservice.Response and protocoordinatorservice.TxStatusInfo are duplicates.

[liran-funaro]

The following:

// blocktx
message TransactionsStatus {
    map<string, StatusWithHeight> status = 1;
}

message StatusWithHeight {
    Status code = 1;
    uint64 block_number = 2;
    uint32 tx_number = 3;
}

// notify
message TxStatusEvent {
    string tx_id = 1;
    protoblocktx.StatusWithHeight status_with_height = 2;
}

// verifier
message Response {
    protocoordinatorservice.TxRef ref = 1;
    protoblocktx.Status status = 2;
}

Can be replaced with:

message TxStatusBatch {
    repeated TxStatus status = 1;
}

message TxStatus {
    protocoordinatorservice.TxRef ref = 1;
    protoblocktx.Status status = 2;
}

[liran-funaro]

protonotify.TxStatusRequest is a duplicate of protoblocktx.QueryStatus