Unable to deploy example kfdef to nonstandard namespace

[accorvin]

With the current codeflare-stack-kfdef.yaml file, you are unable to deploy the stack into any namespace other than opendatahub. We have the namespace hardcoded in the kfdef.

This is at odds with the content in our quick start where we suggest that it is possible to override the default namespace.

IMO we should simply not specify the namespace in the kfdef.