[release-ocm-2.7] MGMT-14871: Copy Day2 BMH if Agent is installing

https://issues.redhat.com//browse/MGMT-14871
Backport to ACM 2.7
Cherry pick of
openshift#5250

Original description:
OCPBUGS-7076
Previously the BMAC would copy the BMH and
Machine CRs of a Day2 worker to the spoke cluster before
the Agent began installing. If the Agent doesn't
start installing within the two hours these CRs
were copied over, the CSRs for these nodes will
not be approved by the machine approver pod.

To prevent this from happening, only copy
the BMH and Machine CRs to the spoke cluster
when the Agent has started installing.

internal/controller/controllers/bmh_agent_controller.go

@@ -40,6 +40,7 @@ import (
 	machinev1beta1 "github.com/openshift/machine-api-operator/pkg/apis/machine/v1beta1"
 	"github.com/pkg/errors"
 	"github.com/sirupsen/logrus"
+	"github.com/thoas/go-funk"
 	corev1 "k8s.io/api/core/v1"
 	k8serrors "k8s.io/apimachinery/pkg/api/errors"
 	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"