Fetch cluster configuration from DNS entries
Instead of semi-hardcoding important configuration values related to the cluster (API, Token Exchange URL, responsible Authentication server etc.) in the script, it is better to retrieve this from the cluster directly.
This patch implements fetching the config values from special DNS TXT values which should be available under _config.${CLUSTER_NAME}.okd.cern.ch
The backend implementation is handled in https://gitlab.cern.ch/paas-tools/okd4-install/-/merge_requests/928
Edited by Jack Henschel