Tekton pipelines provides metrics but users are having trouble while
using it. The main reason is that current metrics is both too much and
too fine-grained.

The idea here is to simplify metrics by reducing the amount of it and
allow users focus on the metrics they really care about.

Linked to https://issues.redhat.com/browse/SRVKP-1528

In addition, we should allow the cluster-admin to disable ServiceMonitor altogether if need be.