feat: add metrics — fix cardinality bug, add outcome/adoption tracking

[gianlucam76]

Metrics (all projectsveltos_-prefixed):

• reconcile_duration_seconds (histogram): cluster_type, cluster_namespace, cluster_name. No feature label (unlike addon-controller's metric of the same name) — EventTrigger processing isn't split by feature type.
• reconcile_outcome_total (counter): cluster_type, cluster_namespace, cluster_name, status, event_trigger_name.
• matching_clusters (gauge): event_trigger_name. New — clusters currently matching an EventTrigger's sourceClusterSelector.
• matching_resources (gauge): event_trigger_name, cluster_type, cluster_namespace, cluster_name. Resources matched by the most recently processed EventReport, independent of whether ClusterProfile creation subsequently succeeds.
• reconcile_last_success_timestamp_seconds (gauge): cluster_type, cluster_namespace, cluster_name, event_trigger_name. New.

Also:

• Fix metric name prefix
• Enable auth-proxy RBAC resources in config/rbac/kustomization.yaml; regenerate manifest.yaml.
• Add manifest/service_monitor.yaml

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