feat(observability): ✨ add VMServiceScrapes + migrate VLogs → VLSingle

- Migrate VLogs CRD to VLSingle (operator.victoriametrics.com/v1beta1)
- Add VMServiceScrape for Forgejo (gitea ns, port http, /metrics)
- Add VMServiceScrape for ArgoCD (argocd ns, port http-metrics)
- Add VMServiceScrape for GARM (garm ns, port metrics)
- Add VMServiceScrape for CoreDNS (kube-system ns, k8s-app: kube-dns)

Ref: IPCEICIS-4618, IPCEICIS-5066

otc/dev.t09.de/stacks/observability/victoria-k8s-stack/manifests/argocd-scrape.yaml

@@ -0,0 +1,14 @@
+apiVersion: operator.victoriametrics.com/v1beta1
+kind: VMServiceScrape
+metadata:
+  name: argocd
+  namespace: observability
+spec:
+  namespaceSelector:
+    matchNames:
+      - argocd
+  selector:
+    matchLabels:
+      app.kubernetes.io/part-of: argocd
+  endpoints:
+    - port: http-metrics

otc/dev.t09.de/stacks/observability/victoria-k8s-stack/manifests/coredns-scrape.yaml

@@ -0,0 +1,14 @@
+apiVersion: operator.victoriametrics.com/v1beta1
+kind: VMServiceScrape
+metadata:
+  name: coredns
+  namespace: observability
+spec:
+  namespaceSelector:
+    matchNames:
+      - kube-system
+  selector:
+    matchLabels:
+      k8s-app: kube-dns
+  endpoints:
+    - port: metrics

otc/dev.t09.de/stacks/observability/victoria-k8s-stack/manifests/forgejo-scrape.yaml

@@ -0,0 +1,15 @@
+apiVersion: operator.victoriametrics.com/v1beta1
+kind: VMServiceScrape
+metadata:
+  name: forgejo
+  namespace: observability
+spec:
+  namespaceSelector:
+    matchNames:
+      - gitea
+  selector:
+    matchLabels:
+      app.kubernetes.io/name: forgejo
+  endpoints:
+    - port: http
+      path: /metrics

otc/dev.t09.de/stacks/observability/victoria-k8s-stack/manifests/garm-scrape.yaml

@@ -0,0 +1,14 @@
+apiVersion: operator.victoriametrics.com/v1beta1
+kind: VMServiceScrape
+metadata:
+  name: garm
+  namespace: observability
+spec:
+  namespaceSelector:
+    matchNames:
+      - garm
+  selector:
+    matchLabels:
+      app.kubernetes.io/name: garm
+  endpoints:
+    - port: metrics

otc/dev.t09.de/stacks/observability/victoria-k8s-stack/manifests/vlogs.yaml

@@ -1,5 +1,5 @@
 apiVersion: operator.victoriametrics.com/v1beta1
-kind: VLogs
+kind: VLSingle
 metadata:
   name: victorialogs
   namespace: observability