Use k8s API to create Gateway-related objects in Gateway controllers.

[michaelbeaumont]

Description

• Using the Kuma store interface makes owner references unusable (see fix(gateway): set owner reference of Kuma Gateway in Gateway API controller #3482).
• See also discussion about cleaner interfaces feat(gateway): add GatewayInstance controller  #3476 (comment).

The foundation for this was added in #3610

[jpeach]

I looked at the Gateway API controller as part of the change to switch Kuma Gateway resources from namespaced to cluster scoped. Just a note to remind us that in the controller, the code that calls K8sNamespacedNameToCoreName() will change as part of this issue, and we ought to use GenerateName to create the name of the Kuma Gateway resource that will be owned by the gateway API resources.

[michaelbeaumont]

@jpeach Now that kuma Gateway resources are cluster-scoped, they can no longer be owned by the namespace-scoped Gateway API objects. Maybe we can just annotate the Gateway/GatewayRoute objects with the namespace/name/uid of the Gateway/HTTPRoute and garbage collect them ourselves.

[jpeach]

@jpeach Now that kuma Gateway resources are cluster-scoped, they can no longer be owned by the namespace-scoped Gateway API objects. Maybe we can just annotate the Gateway/GatewayRoute objects with the namespace/name/uid of the Gateway/HTTPRoute and garbage collect them ourselves.

Ouch, that's unfortunate. Yeh, I don't see an alternative other than doing our own garbage collection when gateway API objects are deleted. We should annotate the objects in both directions so that we can clean up from either end if we need to.