docs: update getting started guides to Gateway API standard channel

Signed-off-by: Lahiru De Silva <lahirude@wso2.com>

Author: NomadXD

docs/getting-started/try-it-out/on-k3d-locally.mdx

@@ -119,7 +119,7 @@ The [Gateway API](https://gateway-api.sigs.k8s.io/) is the Kubernetes-native way
 
 ```bash
 kubectl apply --server-side \
-  -f https://github.com/kubernetes-sigs/gateway-api/releases/download/v1.5.1/experimental-install.yaml
+  -f https://github.com/kubernetes-sigs/gateway-api/releases/download/v1.5.1/standard-install.yaml
 ```
 
 #### cert-manager

docs/getting-started/try-it-out/on-k3d-locally/k3d-prerequisites.sh

@@ -9,7 +9,7 @@ step() {
 
 step "Installing Gateway API CRDs..."
 kubectl apply --server-side \
-  -f https://github.com/kubernetes-sigs/gateway-api/releases/download/v1.5.1/experimental-install.yaml
+  -f https://github.com/kubernetes-sigs/gateway-api/releases/download/v1.5.1/standard-install.yaml
 
 step "Installing cert-manager..."
 helm upgrade --install cert-manager oci://quay.io/jetstack/charts/cert-manager \

docs/getting-started/try-it-out/on-your-environment.mdx

@@ -91,7 +91,7 @@ The [Gateway API](https://gateway-api.sigs.k8s.io/) is the Kubernetes-native way
 
 ```bash
 kubectl apply --server-side \
-  -f https://github.com/kubernetes-sigs/gateway-api/releases/download/v1.5.1/experimental-install.yaml
+  -f https://github.com/kubernetes-sigs/gateway-api/releases/download/v1.5.1/standard-install.yaml
 ```
 
 #### cert-manager