manifests: Improve "autoscale" kustomization

* Remove "base" base: Allows user to use "autoscale" along "base",
  "release", or "test". Example:

  ```yaml
  apiVersion: kustomize.config.k8s.io/v1beta1
  kind: Kustomization
  resources:
  - github.com/kubernetes-sigs/metrics-server/manifests/release?ref=v0.5.0
  - github.com/kubernetes-sigs/metrics-server/manifests/autoscale?ref=v0.5.0
  ```

* Delete metrics-server container resources: Since they are managed by
  the nanny sidecar, re-applying the manifest could restart the deployment
  unnecessarily. This is especially obvious with a GitOps tool like Argo CD,
  which would show a diff between manifest and resources set by the addon-resizer

manifests/autoscale/kustomization.yaml

@@ -1,7 +1,5 @@
 apiVersion: kustomize.config.k8s.io/v1beta1
 kind: Kustomization
-bases:
-  - ../base
 patchesStrategicMerge:
   - patch.yaml
 

manifests/autoscale/patch.yaml

@@ -8,6 +8,10 @@ spec:
   template:
     spec:
       containers:
+        - name: metrics-server
+          # Resources are set by the nanny sidecar
+          resources:
+            $patch: delete
         - name: metrics-server-nanny
           image: k8s.gcr.io/addon-resizer:1.8.11
           resources: