Remove reference to defunct gitlab docker image

see #14164

misc/kubernetes.yml

@@ -1,53 +0,0 @@
----
-apiVersion: apps/v1
-kind: Deployment
-metadata:
-  labels:
-    app: minetest
-  name: minetest
-  namespace: default
-spec:
-  selector:
-    matchLabels:
-      app: minetest
-  template:
-    metadata:
-      labels:
-        app: minetest
-    spec:
-      containers:
-      - image: registry.gitlab.com/minetest/minetest/server:master
-        name: minetest
-        ports:
-        - containerPort: 30000
-          protocol: UDP
-        volumeMounts:
-        - mountPath: /var/lib/minetest
-          name: minetest-data
-        - mountPath: /etc/minetest
-          name: config
-      restartPolicy: Always
-      volumes:
-      - name: minetest-data
-        persistentVolumeClaim:
-          claimName: minetest-data
-      - configMap:
-          defaultMode: 420
-          name: minetest
-        name: config
----
-apiVersion: v1
-kind: Service
-metadata:
-  labels:
-    app: minetest
-  name: minetest
-  namespace: default
-spec:
-  ports:
-  - name: minetest
-    port: 30000
-    protocol: UDP
-  selector:
-    app: minetest
-  type: NodePort