[COMMON][DOC] Add documentation for Montral and GatewayAPI

Add override file to use GatewayAPI as Ingress provider
A precreated GW named "common-gateway" is used.
Added documentation for Montreal like release notes,
Infrastructure guides...

Issue-ID: OOM-3184
Issue-ID: OOM-3242

Change-Id: I18107bac52abf34dbc0b217fd8b7542ba51aab84
Signed-off-by: Andreas Geissler <andreas-geissler@telekom.de>
diff --git a/docs/sections/resources/yaml/common-gateway.yaml b/docs/sections/resources/yaml/common-gateway.yaml
new file mode 100644
index 0000000..3cc1cc5
--- /dev/null
+++ b/docs/sections/resources/yaml/common-gateway.yaml
@@ -0,0 +1,96 @@
+apiVersion: gateway.networking.k8s.io/v1beta1
+kind: Gateway
+metadata:
+  name: common-gateway
+  namespace: istio-ingress
+spec:
+  gatewayClassName: istio
+  listeners:
+    - name: http-80
+      hostname: "*.{{ onap_baseurl }}"
+      port: 80
+      protocol: HTTP
+      allowedRoutes:
+        namespaces:
+          from: All
+    - name: https-443
+      hostname: "*.{{ onap_baseurl }}"
+      port: 443
+      protocol: HTTPS
+      allowedRoutes:
+        namespaces:
+          from: All
+      tls:
+        mode: Terminate
+        certificateRefs:
+          - kind: Secret
+            group: ""
+            name: ingress-tls-secret
+    - name: udp-162
+      protocol: UDP
+      port: 162
+      allowedRoutes:
+        kinds:
+          - kind: UDPRoute
+        namespaces:
+          from: All
+    - name: tcp-4334
+      protocol: TCP
+      port: 4334
+      allowedRoutes:
+        kinds:
+          - kind: TCPRoute
+        namespaces:
+          from: All
+    - name: tcp-9000
+      allowedRoutes:
+        namespaces:
+          from: All
+      hostname: "kafka-api{{ onap_postaddr }}.{{ onap_baseurl }}"
+      port: 9000
+      protocol: TLS
+      tls:
+        certificateRefs:
+          - group: ""
+            kind: Secret
+            name: ingress-tls-secret
+        mode: Terminate
+    - name: tcp-9001
+      allowedRoutes:
+        namespaces:
+          from: All
+      hostname: "kafka-api{{ onap_postaddr }}.{{ onap_baseurl }}"
+      port: 9001
+      protocol: TLS
+      tls:
+        certificateRefs:
+          - group: ""
+            kind: Secret
+            name: ingress-tls-secret
+        mode: Terminate
+    - name: tcp-9002
+      allowedRoutes:
+        namespaces:
+          from: All
+      hostname: "kafka-api{{ onap_postaddr }}.{{ onap_baseurl }}"
+      port: 9002
+      protocol: TLS
+      tls:
+        certificateRefs:
+          - group: ""
+            kind: Secret
+            name: ingress-tls-secret
+        mode: Terminate
+    - name: tcp-9010
+      allowedRoutes:
+        namespaces:
+          from: All
+      hostname: "kafka-bootstrap-api{{ onap_postaddr }}.{{ onap_baseurl }}"
+      port: 9010
+      protocol: TLS
+      tls:
+        certificateRefs:
+          - group: ""
+            kind: Secret
+            name: ingress-tls-secret
+        mode: Terminate