Implement new setup key resource (#178)

This change implements a new resource called SetupKey that manages the
lifecycle of setup keys and stores them in secrets.

A major change here is that we are also switching to using SSA for
resource management.

Part of #172

Signed-off-by: Philip Laine <philip.laine@gmail.com>

internal/ssautil/ssautil.go

@@ -0,0 +1,22 @@
+package ssautil
+
+import (
+	"k8s.io/apimachinery/pkg/runtime"
+	metav1ac "k8s.io/client-go/applyconfigurations/meta/v1"
+	"sigs.k8s.io/controller-runtime/pkg/client"
+	"sigs.k8s.io/controller-runtime/pkg/client/apiutil"
+)
+
+func OwnerReference(owner client.Object, scheme *runtime.Scheme) (*metav1ac.OwnerReferenceApplyConfiguration, error) {
+	gvk, err := apiutil.GVKForObject(owner, scheme)
+	if err != nil {
+		return nil, err
+	}
+	return metav1ac.OwnerReference().
+		WithAPIVersion(gvk.GroupVersion().String()).
+		WithKind(gvk.Kind).
+		WithName(owner.GetName()).
+		WithUID(owner.GetUID()).
+		WithController(true).
+		WithBlockOwnerDeletion(true), nil
+}