refactor: improve project structure, idempotency, and security

- Replace interactive python setup script with native Ansible vars_prompt.

- Add missing Prometheus helm values template for resource management on Raspberry Pi.

- Replace deprecated apt_key module usage with modern keyring file download.

- Add project files: requirements.txt, requirements.yml, and .gitignore.

roles/prometheus/templates/values.yml.j2

@@ -0,0 +1,56 @@
+# Prometheus community Helm Chart values for Raspberry Pi (kube-prometheus-stack)
+# Optimisé pour des environnements à ressources limitées (ex: Raspberry Pi)
+
+prometheus:
+  prometheusSpec:
+    # Réglage des ressources mémoire/CPU pour éviter les OOM-kills sur les RPi
+    resources:
+      requests:
+        cpu: 100m
+        memory: 512Mi
+      limits:
+        cpu: 1000m
+        memory: 1024Mi
+    # Rétention des données
+    retention: 7d
+    retentionSize: 10Gi
+
+alertmanager:
+  enabled: true
+  alertmanagerSpec:
+    resources:
+      requests:
+        cpu: 50m
+        memory: 128Mi
+      limits:
+        cpu: 200m
+        memory: 256Mi
+
+grafana:
+  enabled: true
+  resources:
+    requests:
+      cpu: 100m
+      memory: 256Mi
+    limits:
+      cpu: 500m
+      memory: 512Mi
+
+# Désactivation optionnelle de certains services non requis ou consommateurs
+kubeStateMetrics:
+  resources:
+    requests:
+      cpu: 10m
+      memory: 64Mi
+    limits:
+      cpu: 100m
+      memory: 128Mi
+
+nodeExporter:
+  resources:
+    requests:
+      cpu: 10m
+      memory: 32Mi
+    limits:
+      cpu: 100m
+      memory: 64Mi