Improve kustomization usage

Ensure that the `manifest/base` folder can be used as a standalone
kustomization resource.

Add a new subfolder `manifest/gpu` which uses `manifest/base` with
additional GPU related patches.

kubernetes/manifest/gpu/ollama-statefulset-gpu.yaml

@@ -0,0 +1,17 @@
+apiVersion: apps/v1
+kind: StatefulSet
+metadata:
+  name: ollama
+  namespace: open-webui
+spec:
+  selector:
+    matchLabels:
+      app: ollama
+  serviceName: "ollama"
+  template:
+    spec:
+      containers:
+      - name: ollama
+        resources:
+          limits:
+            nvidia.com/gpu: "1"