Add Prometheus instrumentation to Reconcile #16
Description
We should add Prometheus instrumentation to the controller in order to track the following metrics:
- octops_ingress_reconcile_success: Counter for each reconcile event that succeeded
- octops_ingress_reconcile_failed: Counter for each reconcile event that failed
- octops_ingress_reconcile_duration_ms: Time taken to complete a reconcile event in milliseconds
The gameserver-ingress-controller should expose the [PORT]/metrics endpoint that will be scrapped by Prometheus. The implementation should be extensible and take into consideration that new metrics might be added to the future.
Refereces to the Prometheus instrumentation for Go applications can be found on https://prometheus.io/docs/guides/go-application/