[Feature Request] Change namespace metric label to be less ambiguous, preventing conflicts

[wise0wl]

Is your feature request related to a problem? Please describe.

Currently all metrics have a label namespace attached. However this label namespace is the prometheus default label rename for the default __meta_kubernetes_namespace label. This causes conflicts and subsequent issues when in Kubernetes environments monitored by Prometheus.

Describe the solution you'd like

Allow this label to be either set to something like temporal_namespace by default, and / or make it configurable.

[cretz]

While we can't change what's there, I don't see why we couldn't have a metric_attribute_prefix that can be set. Will defer to @Sushisource.