fix: #337 Added a separate method to sign transaction bytes

[satran004]

• New methods have been added that avoid de-serializing the full transaction bytes, thereby preventing any compatibility issues.

 public byte[] sign(byte[] transactionBytes, SecretKey secretKey)
public byte[] sign(byte[] transactionBytes, HDKeyPair hdKeyPair)

• Old sign methods are delegating to above new methods for tx signing

[satran004]

@Sotatek-HuyLe3 Please check TransactionBytes class in this PR. We can use this class or something like this in Yaci to fix incorrect metadata cbor.

[Sotatek-HuyLe3a]

Thanks, this class could be useful for fixing incorrect metadata cbor.