gitops: observability stack (Loki/Promtail/Grafana), Grafana Ingress, Argo multi-source

- Add gitops/observability umbrella chart with vendored Helm deps
- Grafana Ingress: Traefik, letsencrypt-prod, grafana.k8s.selair.it + root_url
- Argo Application: spec.sources (onelab + onelab-obs)
- OneLab: configuration secret override, compliance/LDAP values, logs.path /logs
- Docs: OBSERVABILITY, BOOTSTRAP, README, instance-overrides example

Made-with: Cursor

gitops/charts/onelab/templates/workloads.yaml

@@ -76,7 +76,7 @@ spec:
         {{- if .config }}
         - name: configurations
           secret:
-            secretName: onelab-configurations
+            secretName: {{ include "onelab.configurationSecretName" $root }}
         {{- end }}
         {{- if eq $root.Values.persistence.mode "hostPath" }}
         {{- if has "logs" .mounts }}