Improve network policies concept (#18091)

* Adopt website style guidelines

* Tweak wording

Co-Authored-By: cmluciano <cmluciano@cruznet.org>

* Make sample NetworkPolicies downloadable

Co-authored-by: cmluciano <cmluciano@cruznet.org>

content/en/examples/service/networking/network-policy-allow-all-egress.yaml

@@ -0,0 +1,11 @@
+---
+apiVersion: networking.k8s.io/v1
+kind: NetworkPolicy
+metadata:
+  name: allow-all-egress
+spec:
+  podSelector: {}
+  egress:
+  - {}
+  policyTypes:
+  - Egress

content/en/examples/service/networking/network-policy-allow-all-ingress.yaml

@@ -0,0 +1,11 @@
+---
+apiVersion: networking.k8s.io/v1
+kind: NetworkPolicy
+metadata:
+  name: allow-all-ingress
+spec:
+  podSelector: {}
+  ingress:
+  - {}
+  policyTypes:
+  - Ingress

content/en/examples/service/networking/network-policy-default-deny-all.yaml

@@ -0,0 +1,9 @@
+apiVersion: networking.k8s.io/v1
+kind: NetworkPolicy
+metadata:
+  name: default-deny-all
+spec:
+  podSelector: {}
+  policyTypes:
+  - Ingress
+  - Egress

content/en/examples/service/networking/network-policy-default-deny-egress.yaml

@@ -0,0 +1,9 @@
+---
+apiVersion: networking.k8s.io/v1
+kind: NetworkPolicy
+metadata:
+  name: default-deny-egress
+spec:
+  podSelector: {}
+  policyTypes:
+  - Egress

content/en/examples/service/networking/network-policy-default-deny-ingress.yaml

@@ -0,0 +1,9 @@
+---
+apiVersion: networking.k8s.io/v1
+kind: NetworkPolicy
+metadata:
+  name: default-deny-ingress
+spec:
+  podSelector: {}
+  policyTypes:
+  - Ingress