validate cidr

only accept validated cidr.
And fix the error handle when network-isotate is diabled.
And remove the useless crd.

Signed-off-by: Duan Jiong <djduanjiong@gmail.com>

config/crds/network.kubesphere.io_namespacenetworkpolicies.yaml

@@ -101,6 +101,7 @@ spec:
                               description: CIDR is a string representing the IP Block
                                 Valid examples are "192.168.1.1/24"
                               type: string
+                              pattern: ^([0-9]{1,3}\.){3}[0-9]{1,3}(\/([0-9]|[1-2][0-9]|3[0-2]))$
                             except:
                               description: Except is a slice of CIDRs that should
                                 not be included within an IP Block Valid examples