feat: Manage prometheus resources

[tolusha]

What does this PR do?

1. New metrics package (pkg/deploy/metrics/) — a new reconciler that manages Prometheus resources:
   • ServiceMonitor objects for both Che Server (che-host) and DWO (devworkspace-controller)
   • RBAC (Role + RoleBinding) granting the prometheus-k8s service account access to scrape metrics endpoints
   • Adds the openshift.io/cluster-monitoring: "true" label to the operator namespace so OpenShift's built-in monitoring stack discovers the ServiceMonitors
2. New CRD field — spec.devEnvironments.metrics (*bool, defaults to true) to enable/disable DWO metrics collection. Che Server metrics are controlled by the existing spec.components.metrics.enable field.
3. Migration updates — refactored the one-time migration logic to also add the app.kubernetes.io/part-of=che.eclipse.org label to existing ServiceMonitor objects, and generally cleaned up the migration code (replaced
   logrus with structured logging, simplified label-setting logic).

Screenshot/screencast of this PR

N/A

What issues does this PR fix or reference?

https://redhat.atlassian.net/browse/CRW-8629
https://redhat.atlassian.net/browse/CRW-8589
https://redhat.atlassian.net/browse/CRW-8315

How to test this PR?

TODO

Common Test Scenarios

• Deploy Eclipse Che
• Start an empty workspace
• Open terminal and build/run an image
• Stop a workspace
• Check operator logs for reconciliation errors or infinite reconciliation loops

PR Checklist

As the author of this Pull Request I made sure that:

• The Eclipse Contributor Agreement is valid
• Code produced is complete
• Code builds without errors
• Tests are covering the bugfix
• The repository devfile is up to date and works
• Relevant user documentation updated
• Relevant contributing documentation updated
• CI/CD changes implemented, documented and communicated

Reviewers

Reviewers, please comment how you tested the PR when approving it.

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