As as dev I want to easily add and understand which input results in triggering a nodepool upgrade.

There's many scattered things that triggers nodepool rolling upgrade on change.
For code sustainability it'd be good to try to have a common abstraction that discovers all of them based on an input and return the authoritative hash for any targeted config version in time.
Related https://github.com/openshift/hypershift/pull/4057
https://github.com/openshift/hypershift/pull/3969#discussion_r1587198191