Add feature flag to skip consumer sync to Konnect about kubernetes-ingress-controller

[mheap]

add --SkipConsumerKonnectSync feature flag which bypasses consumers when syncing in Konnect

To be specific, the idea is to skip consumer credentials, not the consumers themselves.

We should also use the FeatureGates functionality rather than a new flag as we have pre-wired usage metrics for feature gates

[lahabana]

There was an offline discussion around only using FeatureGates because they have metrics. Maybe we should just rework the telemetry lib to add telemetry for this.

[pmalek]

No need to extend the telemetry package. It's already capable of sending "fixed payloads", which is done in KIC via:

kubernetes-ingress-controller/internal/manager/telemetry/reports.go

Lines 86 to 92 in 513db87

	fixedPayload := Payload{
	"v": metadata.Release,
	"kv": kongVersion,
	"db": kongDB,
	"rf": routerFlavor,
	"id": instanceIDProvider.GetID(), // universal unique identifier for this system
	}

.

It's just a matter of serializing config or CLI flags/envs.

[lahabana]

@mheap agrees that we don't need a FeatureGate for this.