Add delete confirmation and warning (#31)

* Update delete-yatai.sh

* Update delete-yatai.sh

delete-yatai.sh

@@ -1,10 +1,20 @@
 #!/bin/bash
 
-# Use helm to remove yatai installation
+echo -e "\033[01;31mWarning: this will permanently delete all Yatai resources, existing model deployments, and in-cluster minio, postgresql DB data. Note that external DB and blob storage will not be deleted.\033[00m"
+read -p "Are you sure to delete Yatai in cluster '$(kubectl config current-context)'? [y/n] " -n 1 -r
+echo # move to a new line
+if [[ ! $REPLY =~ ^[Yy]$ ]]
+then
+    [[ "$0" = "$BASH_SOURCE" ]] && exit 1 || return 1 # handle exits from shell or function but don't exit interactive shell
+fi
+
+echo "Uninstalling yatai helm chart from cluster.."
 helm uninstall yatai -n yatai-system
 
-# Remove additional yatai related namespaces
+echo "Removing additional yatai related namespaces and resources.."
 kubectl delete namespace yatai-components
 kubectl delete namespace yatai-operators
 kubectl delete namespace yatai-builders
 kubectl delete namespace yatai
+
+echo "Done"