create getTransactionRequestAuthCodeHash function and sendSecurityChallenge

To generate an authCode to be sent OOB to the customer so they can confirm a transaction.

We'll produce a hash which includes the authCode (say 5 character pin) the details of the transaction it should confirm i.e. something like:

def getAuthCodeHash = sha256 (authCode +
account +
amount +
currency +
counterparty.(all fields) +
transactionRequestId)

Then we'll create a new connector function: sendSecurityChallenge (bankId: BankId, accountId: AccountId, userId: String, transactionRequestType: TransactionRequestType, transactionRequestId: String, authCode: String, authCodeHash: String)

which is similar to createSecurityChallenge but lets us send the authCode and its hash.

e.g.

authCode = Random(5 numbers)

authCodeHash = getAuthCodeHash(...)

sendSecurityChallenge(....challengeId, authCode, authCodeHash)
note we create the challengeId locally so we can store it in the transaction request