Add a custom Statsd Client on AWS Provider to push metrics directly to Cloudwatch Metrics.

[mariotaddeucci]

Airflow supports to use a custom StatsdClient setting the config statsd_custom_client_path on metrics section.
By extending statsd.StatsClient we can override the constructor and the _send method, to send directly to cloudwatch metrics, simplifying the way to export metrics to AWS.
This class can be added on apache-airflow-providers-amazon adding the metrics submodule.

[metrics]
statsd_custom_client_path = airflow.providers.amazon.aws.metrics.cloudwatch.StatsClient

If t makes sense, I am willing to submit a PR!

[potiuk]

I think it would be much more powerful to comment and vote on the https://cwiki.apache.org/confluence/display/AIRFLOW/AIP-49+OpenTelemetry+Support+for+Apache+Airflow - this will be way more powerful and once it is implemented the old way of collecting metrics will be deprecated.

CloudWatch has full support for OpenTelemetry https://docs.aws.amazon.com/AmazonCloudWatch/latest/monitoring/CloudWatch-Agent-open-telemetry.html

The "metrics" replacement with OpenTelemetry in Airflow shoudl be easy to implement for 2.4.0 once discsusion is complete and voting done and this is the first time any modification like this would happen in 2.4.0 only so I think it makes much more sense.