Add enhancement for EtcdBackup CRD for OADP integration

Introduces a new EtcdBackup CRD in the hypershift.openshift.io/v1beta1
API group that serves as the contract between the OADP HyperShift plugin
and the Hypershift Operator for triggering etcd backups. A controller in
the HO orchestrates snapshot and upload Jobs while keeping management
credentials isolated from HCP namespaces.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
Signed-off-by: Juan Manuel Parrilla Madrid <jparrill@redhat.com>

Author: jparrill