Fix observability and startup probe issues

- Explicitly configure management port 8081 in application.yaml to resolve connection refused errors.
- Adjust startupProbe failure threshold and initial delay in Helm chart to allow for a one-minute startup time.
- Update vmagent to use Kubernetes pod discovery for metrics scraping, adding necessary RBAC Role and RoleBinding.
- Introduce 'json-logging' Spring profile for structured console logging in Kubernetes.
- Add support for VictoriaMetrics Operator CRDs (VMSingle, VMAgent, VMPodScrape) to leverage the existing operator in the cluster.
- Review and refine observability templates for better integration with the VictoriaMetrics stack.

Co-authored-by: devitq <118541411+devitq@users.noreply.github.com>

deploy/helm/movienight/templates/observability/rbac.yaml

@@ -0,0 +1,27 @@
+{{- if and .Values.observability.enabled .Values.observability.vmagent.enabled (not .Values.observability.victoriaMetrics.operator.enabled) }}
+apiVersion: rbac.authorization.k8s.io/v1
+kind: Role
+metadata:
+  name: {{ include "movienight.vmagentName" . }}
+  labels:
+    {{- include "movienight.componentLabels" (dict "root" . "component" "vmagent") | nindent 4 }}
+rules:
+  - apiGroups: [""]
+    resources: ["pods", "nodes", "nodes/proxy", "services", "endpoints"]
+    verbs: ["get", "list", "watch"]
+---
+apiVersion: rbac.authorization.k8s.io/v1
+kind: RoleBinding
+metadata:
+  name: {{ include "movienight.vmagentName" . }}
+  labels:
+    {{- include "movienight.componentLabels" (dict "root" . "component" "vmagent") | nindent 4 }}
+roleRef:
+  apiGroup: rbac.authorization.k8s.io
+  kind: Role
+  name: {{ include "movienight.vmagentName" . }}
+subjects:
+  - kind: ServiceAccount
+    name: {{ include "movienight.serviceAccountName" . }}
+    namespace: {{ .Release.Namespace }}
+{{- end }}