feat: Add Kubernetes manifests for NetHack server

- Creates Kubernetes deployment, service, and PVC manifests to run a multiplayer NetHack server.
- Uses the pre-built matsuu/nethack-server:latest image.
- Configures the service to expose port 4000 externally and correctly route traffic to the container's port 23.
- Adds a .gitignore file to exclude temporary directories.

k8s/pvc.yaml

@@ -0,0 +1,11 @@
+apiVersion: v1
+kind: PersistentVolumeClaim
+metadata:
+  name: nethack-pvc
+  namespace: nethack
+spec:
+  accessModes:
+    - ReadWriteOnce
+  resources:
+    requests:
+      storage: 1Gi