Improve user experience in Get Started guide for NGF

[shaun-nx]

Overview

The goal of this change is to enable users to get up-and-running faster when deploying the example configurations in the NGF Get Started guide.

How it works today

When a user is asked to create an example application they must follow several steps:

1. Create a file called cafe.yaml
2. Copy the contents of the cafe deployment into cafe.yaml
3. Save the file
4. Run kubectl apply -f cafe.yaml

Proposed change

Enable users to accomplish all of the steps above with a single command.
This command will create the .yaml file with the required contents and apply the resources to the cluster.

Below is an example what this command will look like

cat <<EOF > gateway.yaml
apiVersion: gateway.networking.k8s.io/v1
kind: Gateway
metadata:
  name: gateway
spec:
  gatewayClassName: nginx
  listeners:
  - name: http
    port: 80
    protocol: HTTP
    hostname: "*.example.com"
EOF
kubectl apply -f gateway.yaml