Only use Hypervisor CRD in onboarding

[fwiesel]

All the necessary information is now in the CRD, so we can stop polling the information from the node.

[github-actions]

Merging this branch will increase overall coverage

Impacted Packages	Coverage Δ	🤖
github.com/cobaltcore-dev/openstack-hypervisor-operator/internal/controller	37.42% (+4.73%)	👍

---

Coverage by file

Changed files (no unit tests)

Changed File	Coverage Δ	Total	Covered	Missed	🤖
github.com/cobaltcore-dev/openstack-hypervisor-operator/internal/controller/node_eviction_label_controller.go	40.54% (ø)	74	30	44
github.com/cobaltcore-dev/openstack-hypervisor-operator/internal/controller/onboarding_controller.go	2.79% (+0.24%)	215 (-20)	6	209 (-20)	👍
github.com/cobaltcore-dev/openstack-hypervisor-operator/internal/controller/utils.go	32.61% (ø)	46	15	31

Please note that the "Total", "Covered", and "Missed" counts above refer to code statements instead of lines of code. The value in brackets refers to the test coverage of that file in the old version of the code.