deploy: tune external-disk-provisioner flow control

We should consider the default quota of ECS OpenAPI.
The current quota for CreateDisk/DeleteDisk is 500/60s. Each cycle needs 3 API call:
create:
- create PV
delete:
- delete PV
- patch PV finalizer

We set the qps of csi-attacher to 25 to support 500/60s create+delete operations. This is 5x of the default config.

deploy/chart/templates/controller.yaml

@@ -93,8 +93,8 @@ spec:
             - --extra-create-metadata=true
             - --default-fstype=ext4
             - --v=5
-            - --kube-api-qps=10
-            - --kube-api-burst=20
+            - --kube-api-qps=25
+            - --kube-api-burst=50
           volumeMounts:
             - name: disk-provisioner-dir
               mountPath: /csi