Allow cross namespace waypoint capture

[hzxuzhonghu]

What would you like to be added:

Currently we have supported namespace/service waypoint capture since kmesh v0.4, plus istio 1.22+

As istio upstream has supported, cross namespace waypoint in the upcoming 1.23 release, we need to figure out what do we miss in the kmesh to support it.

Why is this needed:

[hzxuzhonghu]

As to how to use that feature, it requires user to set

	// AmbientUseWaypointLabelLabel is the label used to specify which waypoint should be used for a given pod, service, etc...
	AmbientUseWaypointLabel = "istio.io/use-waypoint"

alongside with

/ AmbientUseWaypointNamespaceLabel is a label used to indicate the namespace of the waypoint (referred to by AmbientUseWaypointLabel).
	// This allows cross-namespace waypoint references. If unset, the same namespace is assumed.
	AmbientUseWaypointNamespaceLabel = "istio.io/use-waypoint-namespace"

Besides that, no other api is changed. So in kmesh, we may not need to to do much work on this.

But some test coverage and document is needed

[YaoZengzeng]

/assign