buildkitd: Fix HPA label selectors by splitting envoy cluster_name
Kubernetes did not like the label selector on cluster_name
that
contained '|' delimited information.
Configure the "envoy-stats-monitor" PodMonitor
to relabel scraped
metrics and split the cluster_name
label into distinct host/port/name
labels.
Reconfigure HPA to select on cluster_name: "inbound"
and
cluster_port: "1234"
to only sum active connections to buildkitd.
Bug: T327416