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.
There are currently 2 issues with the Kubernetes manifest:
- open-webui-deployment refers to ollama-webui-pvc but not included in
kustomization.yaml, causing issue if using GPU deployment
- ollama-webui-pvc is using the wrong namespace
This commit fixes both issue.