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/secret-configurations.yaml

@@ -1,3 +1,4 @@
+{{- if not .Values.configuration.existingSecretName }}
 {{- $cfg := fromYaml (.Files.AsConfig) }}
 apiVersion: v1
 kind: Secret
@@ -11,3 +12,4 @@ type: Opaque
 stringData:
   configurations.yml: |
 {{- tpl (index $cfg "configurations.gotmpl") . | nindent 4 }}
+{{- end }}