Missing Documentation for deletion of node from RAC Custer

[s1saurabh]

https://github.com/oracle/docker-images/tree/main/OracleDatabase/RAC/OracleRealApplicationClusters is missing Documentation for deletion of node from RAC Custer

[s1saurabh]

Found way to do though, pls add to documentation-

docker exec racnode1 /bin/sh -c "sudo -E /opt/scripts/startup/DelNode.sh <node_to_be_deleted>"
docker stop <<<node_to_be_deleted>>>
docker rm <<node_to_be_deleted>>>

[s1saurabh]

Raised merge request #2416