fa4c8679ed rpc: Avoid creating non-standard raw transactions (MarcoFalke)
Pull request description:
Multiple OP_RETURN outputs in a transaction are not standard and unlikely to be relayed, so avoid creating them.
Apart from that, the logic was broken in that it duplicated the same hex-data for each data output: Closes#14868.
Tree-SHA512: b08d08062b5622e8a7b497e490ccaf53b06e844c863fda3bf3f932a98684a809e8341aeb98232059a795afb32d8770a6c5591a66f8e6ee372b672af245607887