make PollingInterval configurable to speed up autoscaling reaction time

[lx1036]

Proposal

When create a HTTPScaledObject, operator will create a ScaledObject or skip creation, the ScaledObject PollingInterval field is a const 15:

const (
	soPollingInterval = 15

)

func NewScaledObject(
	namespace string,
	name string,
	labels map[string]string,
	annotations map[string]string,
	workloadRef v1alpha1.ScaleTargetRef,
	scalerAddress string,
	minReplicas *int32,
	maxReplicas *int32,
	cooldownPeriod *int32,
) *kedav1alpha1.ScaledObject {
	return &kedav1alpha1.ScaledObject{
		TypeMeta: metav1.TypeMeta{
			APIVersion: kedav1alpha1.SchemeGroupVersion.Identifier(),
			Kind:       ObjectKind(&kedav1alpha1.ScaledObject{}),
		},
		ObjectMeta: metav1.ObjectMeta{
			Namespace:   namespace,
			Name:        name,
			Labels:      labels,
			Annotations: annotations,
		},
		Spec: kedav1alpha1.ScaledObjectSpec{
			ScaleTargetRef: &kedav1alpha1.ScaleTarget{
				APIVersion: workloadRef.APIVersion,
				Kind:       workloadRef.Kind,
				Name:       workloadRef.Name,
			},
			PollingInterval: ptr.To[int32](soPollingInterval),
			CooldownPeriod:  cooldownPeriod,
			MinReplicaCount: minReplicas,
			MaxReplicaCount: maxReplicas,
			Advanced: &kedav1alpha1.AdvancedConfig{
				RestoreToOriginalReplicaCount: true,
			},
			Triggers: []kedav1alpha1.ScaleTriggers{
				{
					Type: soTriggerType,
					Metadata: map[string]string{
						ScalerAddressKey:    scalerAddress,
						HTTPScaledObjectKey: name,
					},
				},
			},
		},
	}

It should be configurable like CooldownPeriod field, so When I speed up autoscaling reaction time, I can set PollingInterval=1, Keda external scaler get metrics every 1s.

Use-Case

No response

Is this a feature you are interested in implementing yourself?

Yes

Anything else?

No response