Support SASL AWS_MSK_IAM auth method

[valmoz]

It would be great if this library supported also AWS MSK IAM auth method, implementing something similar to what was implemented for this go library: https://github.com/segmentio/kafka-go/tree/main/sasl/aws_msk_iam_v2

[valmoz]

https://docs.aws.amazon.com/msk/latest/developerguide/security_iam_service-with-iam.html

[valmoz]

I created a PR related to this issue: #74