Add binder for AWS SDK v2 metrics

[john-karp]

Please describe the feature request.
Micrometer users who would like the SDK metrics published to their micrometer registry need an implementation of the MetricPublisher interface that can serve as a binder for micrometer. (AWS SDKv2 for Java itself only supports publishing its metrics to CloudWatch.)

Rationale
Most micrometer users that use the AWS SDK probably want the metrics going to their own registry, not directly to a CloudWatch endpoint.

Additional context
A prior comment about the needed work: aws/aws-sdk-java-v2#23 (comment)
I found this implementation, but I'm not sure of its license etc: https://gist.github.com/PatrykGala/e4aec004eb55cd8cbdee328f217771c7
OTEL project is working on something equivalent: open-telemetry/opentelemetry-java-instrumentation#13831