Submit binary transaction endpoint

[lrettig]

We don't currently have one of these. The TxService.SubmitTransaction endpoint accepts a Transaction type which is structured and does not contain binary data (aside from the signature):

api/proto/spacemesh/v1/types.proto

Lines 105 to 116 in 279f08c

	message Transaction {
	TransactionId id = 1;
	oneof data {
	CoinTransferTransaction coin_transfer = 2;
	SmartContractTransaction smart_contract = 3;
	}
	AccountId sender = 4; // tx originator, should match signer inside Signature
	GasOffered gas_offered = 5; // gas price and max gas offered
	Amount amount = 6; // amount of coin transfered in this tx by sender
	uint64 counter = 7; // tx counter aka nonce
	Signature signature = 8; // sender signature on transaction
	}

Per spacemeshos/SMIPS#23 it looks like we need an endpoint to receive signed, binary tx data. Note that the existing, old API does contain an endpoint that does this (SubmitTransaction).

CC @avive

[avive]

I think that this is just an oversight on our part that we should correct. TxService.SubmitTransaction() should accept a byte[] and clients are expected to pass an XDR encoded transaction which includes the signature. Clients need to generate this blob based on the transactions syntax spec - similar to how Smapp and CLIwallet do this today.

[avive]

We will need to update all transactions related api methods to support the new sm tx format - this is part of the reason I'm pushing for a spec via the smip asap.