Show function invocation count for Knative functions
Problem to solve
Users would like to know how often their function is invoked.
(Include use cases, benefits, and/or goals)
When Prometheus is installed on the related cluster, add an invocation chart to the function detail view
If Prometheus is not installed, inform the user that they must install Prometheus in order to view invocations.
What does success look like, and how can we measure that?
(If no way to measure success, link to an issue that will implement a way to measure this)