Add k8s events to reconcilers

[manno]

Fleet writes information about deployments and errors into the status of resources. To assist users with troubleshooting, e.g. when they don't have access to the logs, we can record k8s events.

• record events for critical/terminal failures
• record events for noteworthy deployment steps
• don't add too many events, keep logging separate from events
• events should use the past tense

Log and debug messages still exists for details and tracing.

See:

• https://book-v1.book.kubebuilder.io/beyond_basics/creating_events