Refactor ParentRefAttachmentStatus

[sarthyparty]

Describe the bug

// ParentRefAttachmentStatus describes the attachment status of a ParentRef.
type ParentRefAttachmentStatus struct {
	// AcceptedHostnames is an intersection between the hostnames supported by an attached Listener
	// and the hostnames from this Route. Key is <gatewayNamespacedName/listenerName>, value is list of hostnames.
	AcceptedHostnames map[string][]string
	// FailedConditions are the conditions that describe why the ParentRef is not attached to the Gateway, or other
	// failures that may lead to partial attachments. For example, a backendRef could be invalid, but the route can
	// still attach. The backendRef condition would be displayed here.
	FailedConditions []conditions.Condition
	// ListenerPort is the port on the Listener that the Route is attached to.
	ListenerPort v1.PortNumber
	// Attached indicates if the ParentRef is attached to the Gateway.
	Attached bool
}

This structure mentions ListenerPort as a single port, however parent refs can attach to many listeners and they can have different ports. It is difficult to figure out what bugs this may create, but assuming something with status and this needs a refactor.