docs: Update docs for NetworkFence

This patch updates the docs for NetworkFence with
NetworkFenceClassName related changes.

Signed-off-by: Niraj Yadav <niryadav@redhat.com>

Author: black-dragon74

docs/networkfence.md

@@ -2,7 +2,15 @@
 
 NetworkFence is a cluster-scoped custom resource that allows Kubernetes to invoke "Network fence" operation on a storage provider.
 
-The user needs to specify the list of CIDR blocks on which network fencing operation will be performed; alongside the csi driver name.
+The user needs to specify the list of CIDR blocks on which network fencing operation will be performed along with either of
+`networkFenceClassName` or the csi driver name. When a `networkFenceClassName` is specified, the secret name, namespace
+and parameters are read from the `NetworkFenceClass`.
+
+When both `networkFenceClassName` and `driver` are specified `networkFenceClassName` has the higher precedence.
+
+> **Note:** Specifying `driver`, `secret` and `parameters` inside `NetworkFence` is deprecated, users are encouraged
+> to use `networkFenceClassName` along with a `NetworkFenceClass` instead.
+
 The creation of NetworkFence CR will add a network fence, and its deletion will undo the operation.
 
 ## Fence Operation
@@ -13,10 +21,14 @@ kind: NetworkFence
 metadata:
   name: network-fence-sample
 spec:
-  driver: example.driver
+  networkFenceClassName: network-fence-class
   cidrs:
     - 10.90.89.66/32
     - 11.67.12.42/24
+  # The fields driver, secret and parameters are deprecated.
+  # It is recommended to use networkFenceClassName to specify these.
+  # Note: `driver` is referred to as the `provisioner` in NetworkFenceClass.
+  driver: example.driver
   secret:
     name: fence-secret
     namespace: default
@@ -26,7 +38,8 @@ spec:
 
 > **Note**: Creation of a NetworkFence CR blocks access to the corresponding CIDR block; which is then unblocked the CR deletion.
 
-- `provisioner`: specifies the name of storage provisioner.
+- `networkFenceClassName`: specifies the name of the NetworkFenceClass.
+- `driver`: specifies the name of storage provisioner.
 - `cidrs`: refers to the CIDR blocks on which the mentioned fence/unfence operation is to be performed.
 - `secret`: refers to the kubernetes secret required for network fencing operation.
   - `name`: specifies the name of the secret