Create /metrics endpoint for controller

[davekonopka]

Create a /metrics endpoint for the controller to expose metrics and potentially use as a liveness probe endpoint.

[stale]

This issue has been automatically marked as stale because it has not had recent activity. It will be closed if no further activity occurs. Thank you for your contributions.

[stale]

This issue has been automatically marked as stale because it has not had recent activity. It will be closed if no further activity occurs. Thank you for your contributions.