* Add hashes for kubernetes 1.29.0, 1.28.5, 1.27.9, 1.26.12

This is removed from kubernetes since 1.25, time to cut some dead code.

* Decouple role kubespray-defaults from download

Avoids doing re-importing the download role on every invocation of
kubespray-defaults (and skipping everything).

This has a measurable effect on playbook performance.

* Update docs refering to moved download defaults