Add L4 ILB Dual-Stack Metrics

[panslava]

This PR adds counting service per ipFamilies, ipFamilyPolicy and Status for L4 ILB DualStack

Count will be stored in a map where key is struct

type L4ILBDualStackServiceState struct {
	// IPFamilies stores spec.ipFamilies of Service
	IPFamilies string
	// IPFamilyPolicy specifies spec.IPFamilyPolicy of Service
	IPFamilyPolicy string
	// Status specifies status of L4 ILB DualStack
	Status L4ILBDualStackServiceStateStatus
}

[panslava]

/assign cezarygerard

[cezarygerard]

use the old metrics with new labels?
adding labels is a safe change

l4ILBCount = prometheus.NewGaugeVec(
	prometheus.GaugeOpts{
		Name: "number_of_l4_ilbs",
		Help: "Number of L4 ILBs",
	},
	[]string{label, "ipFamilies", "ipFamilyPolicy", "status"},
)

or this is not possible with a feature label?

[cezarygerard]

/lgtm

[k8s-ci-robot]

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This pull-request has been approved by: cezarygerard, panslava

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