chore: update labels to use app.kubernetes.io/name format

Refactor Kubernetes resource labels for rabbitmq, mysql, and postgres 
to follow the standardized naming convention of 
app.kubernetes.io/name. This change enhances clarity and conformity 
across resources, improving maintainability and alignment with 
Kubernetes best practices.

kind/postgres.yaml

@@ -40,12 +40,12 @@ metadata:
 spec:
   selector:
     matchLabels:
-      app: postgres
+      app.kubernetes.io/name: postgres
   replicas: 1
   template:
     metadata:
       labels:
-        app: postgres
+        app.kubernetes.io/name: postgres
     spec:
       containers:
       - name: postgres
@@ -93,11 +93,11 @@ kind: Service
 metadata:
   name: postgres
   labels:
-    app: postgres
+    app.kubernetes.io/name: postgres
 spec:
   ports:
   - port: 5432
     nodePort: 5432
   selector:
-    app: postgres
+    app.kubernetes.io/name: postgres
   type: NodePort