Fix installation of `apiservice` in `Makefile`

[afritzler]

Describe the bug

The following installation routines are wrong as we don not use CRDs but instead API services:

.PHONY: install-ironcore-net
install-ironcore-net: manifests ## Install ironcore-net CRDs into the K8s cluster specified in ~/.kube/config.
	kubectl apply -k config/ironcore-net/crd

.PHONY: uninstall-ironcore-net
uninstall-ironcore-net: manifests ## Uninstall ironcore-net CRDs from the K8s cluster specified in ~/.kube/config.
	kubectl delete-k config/ironcore-net/crd

This needs to be fixed by installing/uninstalling the apiservices instead.