Add Prometheus configuration for monitoring services

- Created a new prometheus.yml file.
- Configured scrape settings for n8n, n8n-worker, node-exporter, and cadvisor with appropriate targets.

prometheus/prometheus.yml

@@ -0,0 +1,19 @@
+global:
+  scrape_interval: 15s
+
+scrape_configs:
+  - job_name: "n8n"
+    static_configs:
+      - targets: ["n8n:5678"]
+
+  - job_name: "n8n-worker"
+    static_configs:
+      - targets: ["n8n-worker:5679"]
+
+  - job_name: "node-exporter"
+    static_configs:
+      - targets: ["node-exporter:9100"]
+
+  - job_name: "cadvisor"
+    static_configs:
+      - targets: ["cadvisor:8080"]