MADR on SNI format considerations

[lobkovilya]

Description

Current format has a few limitations/issues:

• it does not include the zone, which can lead to collisions when MeshExternalService resources with the same name are both synced from the global control plane and created locally in a zone
• it is opaque to users because it contains a hash, which makes it harder for integrations to construct it reliably
• has special handling for MeshServices (because MS is namespace-scoped and MES/MMZS are cluster-scoped)

  kuma/pkg/xds/generator/zoneproxy/destinations.go

  Lines 58 to 64 in b767362

  	var rName string
  	switch r := any(dest).(type) {
  	case *meshservice_api.MeshServiceResource:
  	rName = r.SNIName(systemNS)
  	default:
  	rName = core_model.GetDisplayName(dest.GetMeta())
  	}

Given that we have now adopted the new resource identifier format, KRI, this is a good opportunity to try to address these issues.