Add TLS support to Prometheus metrics server #2832

Job	Run time
Unit Test (knative/operator)	7m 31s
Unit Test (knative/eventing)	14m 40s
Unit Test (knative/networking)	5m 14s
Unit Test (knative/serving)	10m 49s
Unit Test (knative-extensions/eventing-redis)	6m 20s
Unit Test (knative-extensions/eventing-gitlab)	6m 58s
Unit Test (knative-extensions/eventing-ceph)	5m 47s
Unit Test (knative-extensions/eventing-rabbitmq)	8m 17s
Unit Test (knative-extensions/kn-plugin-admin)	6m 1s
Unit Test (knative-extensions/eventing-github)	7m 18s
Unit Test (knative-extensions/eventing-autoscaler-keda)	7m 51s
Unit Test (knative-extensions/net-contour)	5m 20s
Unit Test (knative-extensions/eventing-kafka-broker)	10m 6s
Unit Test (knative/client)	6m 58s
Unit Test (knative-extensions/net-kourier)	5m 49s
Unit Test (knative-extensions/net-istio)	6m 26s
	2h 1m 25s

Provide feedback