Add/cross-link $subject in https://github.com/openshift/hive/blob/master/docs/troubleshooting.md / https://github.com/openshift/hive/blob/master/docs/clusterpools.md

Shouldn't take much: When claims aren't getting satisfied, look for installs failing consistently (show how to query all CDs for a pool via label eck, it looks like we don't actually label them! HIVE-2597); check the logs for those provisions; usually it's a fix to one of the linked secrets (creds, install-config template, etc.) or cloud quota/throttling.