Unify App Mesh and Istio builtin metric checks

[stefanprodan]

• add App Mesh request duration metric check (requires Envoy 1.10 ref: App Mesh request duration metric check #143)
• add request success rate and duration metrics alias fix: Unify App Mesh and Istio builtin metric checks #145 (backwards compatible)

Flagger	Istio	App Mesh
request-success-rate	istio_requests_total	envoy_cluster_upstream_rq
request-duration	istio_request_duration_seconds_bucket	envoy_cluster_upstream_rq_time_bucket

[praseedasathaye]

@stefanprodan I dont see the metrics envoy_cluster_upstream_rq and envoy_cluster_upstream_rq_time_bucket in App Mesh metrics documentation https://docs.aws.amazon.com/AmazonCloudWatch/latest/monitoring/ContainerInsights-Prometheus-metrics.html#ContainerInsights-Prometheus-metrics-appmesh. Do I need to configure anything else to get these metrics?

[stefanprodan]

You need to install Prometheus as documented here https://docs.flagger.app/install/flagger-install-on-eks-appmesh#install-the-app-mesh-components

[praseedasathaye]

I did install Prometheus now and restarted the pods and I just see only the below metrics.