Refactor Kubernetes deployment process to use manifest files and environment variable substitution

k8s/ingress.yaml

@@ -0,0 +1,21 @@
+apiVersion: networking.k8s.io/v1
+kind: Ingress
+metadata:
+  name: ${APP_NAME}-ingress
+  namespace: ${NAMESPACE}
+  labels:
+    app: ${APP_NAME}
+  annotations:
+    traefik.ingress.kubernetes.io/router.entrypoints: web
+spec:
+  rules:
+  - host: ${HOST}
+    http:
+      paths:
+      - path: /
+        pathType: Prefix
+        backend:
+          service:
+            name: ${APP_NAME}-service
+            port:
+              number: 80