storedVersions lists all versions of CustomResources that were ever persisted.
Tracking these versions allows a migration path for stored versions in etcd.
The field is mutable so a migration controller can finish a migration to another version (ensuring no old objects are left in storage), and then remove the rest of the versions from this list.
Versions may not be removed from spec.versions while they exist in this list.
CustomResourceDefinitionStatus indicates the state of the CustomResourceDefinition