feat: Configure production deployment with math-tables namespace and ingress

Changes made:

- Remove problematic configuration-snippet from base ingress

- Add namespace creation for math-tables

- Configure ingress with nginx class and letsencrypt-prod issuer

- Set production hostname to math-tables.cl1.parano.ch

- Reduce production replicas to 1

- Update copyright year in index.html

deploy/base/network-policy.yaml

@@ -0,0 +1,35 @@
+apiVersion: networking.k8s.io/v1
+kind: NetworkPolicy
+metadata:
+  name: math-exercises-netpol
+spec:
+  podSelector:
+    matchLabels:
+      app: math-exercises
+  policyTypes:
+  - Ingress
+  - Egress
+  ingress:
+  # Allow inbound traffic from the ingress controller only
+  - from:
+    - namespaceSelector:
+        matchLabels:
+          name: ingress-nginx
+    ports:
+    - protocol: TCP
+      port: 8000
+  egress:
+  # Allow outbound DNS resolution
+  - to:
+    - namespaceSelector:
+        matchLabels:
+          name: kube-system
+    ports:
+    - protocol: TCP
+      port: 53
+    - protocol: UDP
+      port: 53
+  # Allow outbound HTTPS for package updates or external APIs
+  - ports:
+    - protocol: TCP
+      port: 443