Add a cluster config sample for user

[goswamig]

What is the URL of the document? The URL to help identify the document.

Which section(s) is the issue in? The sections(s) within the document that have issue in.

What needs fixing and describe the solution you'd like? We are providing eksctl create command to launch a cluster, we can provide a sample cluster config file which will help customer to version/re-use the cluster config. an e.g. cluster-config

Additional context https://github.com/weaveworks/eksctl/tree/main/examples